Reinforcement material and reinforcement structure of structure and method of designing reinforcement material

ABSTRACT

Disclosed is a reinforcing member, which comprises a woven body formed by a weaving process, or a tape-shaped or sheet-shaped body, having a high ductility and high bendability. The reinforcing member is adapted to be installed on a surface of a structure member or a boundary portion of the structure member, or inside a structure member, to reinforce the structure member. The woven body, or a tape-shaped or sheet-shaped body, has a Young&#39;s modulus equal to or less than that of the structure member, and a tensile fracture strain of 10% or more. The Young&#39;s modulus of the reinforcing member is preferably in the range of 1/2 to 1/20, more preferably 1/5 to 1/10, of that of the structure member. Specifically, the Young&#39;s modulus of the woven body is preferably in the range of 500 to 50000 MPa, more preferably 1000 to 10000 MPa. The present invention also provides a reinforced structure using the above reinforcing member.

TECHNICAL FIELD

The present invention relates to a reinforcing member for a structuralbody, a reinforced structure using the reinforcing member, and a methodfor designing the reinforcing member.

BACKGROUND ART

Heretofore, there have been known various techniques (reinforcedstructures, reinforcing members and reinforcing methods) for reinforcinga member of a structural body (hereinafter referred to as “structuremember”). Among them, a conventional technique characterized byinstalling a reinforcing member on the surface of or inside a structuremember subject to reinforcement includes (1) a technique of embedding areinforcing bar in concrete as a substrate, or so-called reinforcedconcrete technique, (2) a technique of driving a bolt or nail into asubstrate, (3) a technique of incorporating a high-strength steel rodinside concrete as a substrate and introducing a tensile force to thesteel rod, (4) a technique of wrapping a steel plate around a structuremember, or so-called steel-plate wrapping technique, and (5) a techniqueof using a so-called continuous-fiber reinforcing member made of carbonor aramid fibers and resin, such as epoxy resin, impregnated therein.

Another conventional technique characterized by installing a reinforcingmember between the respective outer surfaces of adjacent structuremembers includes (6) a technique of forming a space, such as hole orslit, in the structure members, and penetratingly inserting areinforcing member into the space, and (7) a technique of forming aspace in the structure members, penetratingly inserting bundled fibersof a continuous-fiber reinforcing member into the space, and thenspreading out the fibers.

Still another conventional technique characterized by installing areinforcing member on the surface of a flat structure member, such aswall, includes (8) a technique of constraining a reinforcing member by ametal plate formed with a hole, and a bar, such as a metal bar,penetrating the structure member, and (9) a technique of bundling thefibers of a continuous-fiber reinforcing member at the edge of thestructure member, and anchoring the bundled fibers to the edge of thestructure member or another member adjacent to the structure member.

Yet another conventional technique characterized by forming areinforcing member in a cylindrical shape and filling the inner space ofthe cylindrical reinforcing member with filler includes (10) a techniqueof forming an iron reinforcing member in a cylindrical shape, andfilling the inner space of the cylindrical reinforcing member withconcrete to use the obtained reinforcing member as a column.

Yet still another conventional technique characterized by installing aplurality of reinforcing members on the outer surface of a structuremember in a superimposed manner includes (11) a technique of providing aplurality of continuous-fiber reinforcing members on the outer surfaceof a structure member in its vertical and horizontal directions in asuperimposed manner.

Another further conventional technique characterized by providing astrip-shaped reinforcing member on the outer surface of a structuremember includes (12) a technique of providing a strip-shaped(tape-shaped) steel plate or continuous-fiber reinforcing member arounda structure member, (13) a technique of filling epoxy resin along acrack of a substrate in a strip shape, and (14) a technique of fixing astrip-shaped steel plate on the surface of a structure member by use ofepoxy resin or an anchor bolt.

Still a further conventional technique characterized by installing areinforcing member on the outer surface of a junction of structuremembers includes (15) a technique of providing a steel jacket orattaching a continuous-fiber reinforcing member on the outer surface ofa junction of structure members.

An additional conventional technique characterized by using aresin-impregnated reinforcing member includes (16) a technique of usinga so-called continuous-fiber reinforcing member made of carbon or aramidfibers and epoxy resin impregnated therein.

The above techniques (4) to (14) are intended to transmit a shear stressdirectly to a reinforcing member without causing any displacement orpeeling between a substrate and the reinforcing member. For example, theshear reinforcement effect of a reinforced concrete member is said tohave the same mechanism as that of a shear-reinforcing bar, and thereinforced concrete member is designed by assigning a reinforcementamount and coefficients expressing the property and reinforcement effectof a reinforcing member to a design formula of the shear-reinforcingbar. Most of the techniques (3) and (15) also include the step ofinjecting a grouting or resin material between a reinforcing member anda substrate to transmit a shear stress directly to the reinforcingmember. The term “substrate” herein means a material constituting astructure member, and a physical object to which a reinforcing member isto be fixed.

Therefore, an intended reinforcement effect can be obtained only if asubstrate is maintained in its proper state, and no displacement orpeeling is caused between the substrate and the reinforcing member. Thisprerequisite must be guaranteed by the design technique and constructionmanagement.

The reinforcing member, such as the reinforcing bar, the steel rod andthe steel plate, used in the techniques (1) to (4), (6), (8), (10),(12), (14) and (15), has the flexural rigidity and shear rigidity of itsown. Thus, if a substrate is locally subjected to a large strain, thereinforcing member cannot follow the local strain, resulting in loss ofthe reinforcement effect due to the occurrence of local fracture in thesubstrate or local buckling or cracks in the reinforcing member.

In the techniques (12) and (16), the reinforcing member made ofresin-impregnated continuous fibers has the same problem as describedabove due to the flexural and shear rigidities resulting from the effectof resin impregnation in addition to the flexural and shear rigiditiesof the continuous fibers themselves. Further, while this reinforcingmember is designed using a formula based on the assumption that it hasonly tensile rigidity, an intended reinforcement effect is actuallylikely to be lost due to occurrence of bending or local buckling inconsequence of the flexural rigidity and shear rigidity of its own.

The material, such as carbon or aramid fibers, used in the techniques(5), (7), (11) and (16), has a fracture strain of 2% to several %, whichis liable to cause damages by the corners of a substrate or theunevenness of the surface of a substrate. Thus, an appropriateconstruction management is essentially required. Further, if thesubstrate has some cracks due to a certain external force, thereinforcing member will be locally broken, which leads to significantdeterioration or disappearance of the reinforcement effect.

In the techniques (1) to (15), if a structure member contacting withanother structure member or having a flat shape or a concavo-convex orirregular surface is reinforced by forming a through-hole therein andpenetratingly inserting a reinforcing member into the through-hole, sucha construction work will involve a problem of high cost and/or extendedperiod, and a particular technology or tool will be required to fix theedge of the reinforcing member or insert the reinforcing member.

In the above technique, a plate, a rod or a bundle of continuous fiberswhich serves as an anchor portion of the reinforcing member (hereinafterreferred to as “anchor member”) has a structure and rigidity differentfrom those of the remaining portion of the reinforcing member. Thus, thethreshold value of the reinforcement effect is undesirably defined bythe threshold values of stress transmission between the reinforcing andanchor members and between the anchor member and the substrate.

Further, the substrate is requited to bear the stress occurring at thefixed portion of the anchor member. Therefore, if the strength of thesubstrate is lowered due to aged deterioration or such an ageddeterioration is calculated, the above technique cannot be applied.

In the technique of introducing a tensile force to a steel rod, if it isapplied to a substrate exhibiting significant creep, such as concrete,the tensile force of the steel rod will be reduced due to the creep, andthe reinforcement effect will be lost across the ages. Further, if theanchor portion of the steel rod is broken by a sudden external force dueto earthquake or the like, the steel rod suddenly freed from the tensileforce will be likely to jump out of the concrete and damage thesurroundings.

Thus, the techniques (1) to (16) are required to install the reinforcingmember by spending an extended time in association with professionalengineers, which involves a high construction cost. The application ofthese techniques is also limited to a specific substrate which can beformed to have a smooth surface as in reinforced concrete, and allows areinforcing member to be brought into close contact therewith so as toform a structure capable of locally transmitting a shear force.

In the so-called continuous-fiber reinforcing member composed ofepoxy-resin-impregnated carbon or aramid fibers in the technique (16),material constants, such as strength and Young's modulus, important inreinforcement design are defined in the state after the fibers areimpregnated with the resin. This reinforcing member is fixed to astructural body, for example, according to the following process asdisclosed in Japanese Patent Laid-Open Publication No. 8-260715.

-   -   (i) Pre-cleaning the surface of a structural body by        removing/repairing stains and damages, such as cracks, thereon,    -   (ii) Applying a primer on the surface,    -   (iii) Uniformly applying a powerful adhesive, such as epoxy        resin, on the surface,    -   (iv) Wrapping the reinforcing member around the structural body        to cover over the surface while stretching the reinforcing        member and keeping it from loosing,    -   (v) Re-applying the adhesive on the surface of the reinforcing        member and impregnating the reinforcing member with the        adhesive, and    -   (vi) Curing the adhesive for given days, and applying on the        surface of the reinforcing member an appropriate coating        material for protecting the reinforcing member from ultraviolet        light or the like.

The reinforcing member is fixed through the many steps as describedabove, and the adhesive in the step (v) can be applied only after theadhesive applied in the step (iii) is completely cured or hardened bychemical action (if the adhesive in the step (v) is prematurely applied,gas bubbles generated during the chemical action will be confined in thereinforcing member to cause the deterioration in strength of thereinforcing member. Thus, the above process has to be completed bytaking a great number of days.

The impregnating step has to be carried out in the working site under astrict construction management. If an external force acts to cause thepeeling between the resin and the continuous fibers, or the resin isdefective in curing or deteriorated due to environmental conditions, thedesign performance of the reinforcing member will be significantlydegraded.

Generally, if a structure member has a non-flat or irregular surface,such as a wall-mounted column, or is joined to or located very close toanother member or non-structural material, such as a column having awindow frame attached thereto, it is difficult to obtain a sufficientreinforcement effect. Further, the interactions between a structuremember and a reinforcing member and between the reinforcing member andthe surrounding are likely to cause deterioration of the reinforcingmember. Furthermore, there is the need for obtaining a sufficientreinforcement effect in a wide range from a small deformation to a largedeformation.

DISCRIPTION OF THE INVENTION

According to a first aspect of the present invention, there is provideda reinforcing member comprising a woven body formed by a weaving processto have a high ductility and high bendability. The reinforcing member isadapted to be installed on a surface of or inside a structure member toreinforce the structure member. The woven body has a Young's modulusequal to or less than that of the structure member, and a tensilefracture strain of 10% or more.

In the reinforcing member set forth in the first aspect of the presentinvention, the Young's modulus of the woven body may be in the range of1/2 to 1/20, preferably 1/5 to 1/10, of that of the structure member.Specifically, the Young's modulus of the woven body may be in the rangeof 500 to 50000 MPa, preferably 1000 to 10000 MPa.

The woven body may have a thickness in the range of 0.2 to 20 mm,preferably 0.5 to 15 mm, more preferably 1 to 10 mm.

The woven body may include yarns made of polyester.

The woven body may have a bending deformation angle of 90-degree ormore, and a shear deformation angle of 2-degree or more.

The reinforcing member set forth in the first aspect of the presentinvention may be heat-set to allow a Young's modulus in a limit state tobe greater than a Young's modulus immediately before fracture. The heatsetting process comprises the steps of heating the reinforcing member toapply a tensile force thereto, and then cooling the reinforcing memberwhile maintaining the tensile force, so as to provide enhanced initialrigidity and Young's modulus to the reinforcing member. In addition, aresin impregnation process may be performed to impregnate thereinforcing member with resin.

This reinforcing member may have an elongation strain in the range of0.1% to 10% in the limit state.

According to a second aspect of the present invention, there is provideda reinforcing member comprising a tape-shaped or sheet-shaped body madeof a rubber-based or resin-based elastic material having a highductility and high bendability. The reinforcing member is adapted to beinstalled on a surface of or inside a structure member to reinforce thestructure member. The tape-shaped or sheet-shaped body has a Young'smodulus equal to or less than that of the structure member, and atensile fracture strain of 10% or more.

In the reinforcing member set forth in the second aspect of the presentinvention, the Young's modulus of the tape-shaped or sheet-shaped bodymay be in the range of 1/2 to 1/20, preferably 1/5 to 1/10, of that ofthe structure member. Specifically, the Young's modulus of thetape-shaped or sheet-shaped body may be in the range of 500 to 50000MPa, preferably 1000 to 10000 MPa.

The tape-shaped or sheet-shaped body may have a thickness in the rangeof 0.2 to 20 mm, preferably 0.5 to 15 mm, more preferably 1 to 10 mm.

The tape-shaped or sheet-shaped body may have a bending deformationangle of 90-degree or more, and a shear deformation angle of 2-degree ormore.

As long as meeting the aforementioned requirement, the reinforcingmember set forth in the second aspect of the present invention may beformed by spraying or applying a rubber-based or resin-based material orfiber-reinforced mortar to the structure member in the working site.While the material cost in this case is higher than the polyester wovenfabric, it is often the case that such a reinforcing member isadvantageous in terms of the ratio of reinforcement effect to cost ascompared to conventional techniques. A Young's modulus in a limit statesuch as a design ultimate state, a fracture strain and a fracture stresscan be calculated based on the stress-strain relationship of thereinforcing member to determine a required reinforcement amount (thethickness of the reinforcing member) and the performance of thestructure member according to an after-mentioned calculation method.

According to third and fourth aspects of the present invention, thereare provided two types of reinforced structures for a structural body.The reinforced structures comprise the reinforcing members set forth inthe first and second aspects of the present invention, respectively. Inthese reinforced structures, the reinforcing member is fixed on asurface of or inside a substrate which constitutes a structure member ofthe structural body and consists of at least one material, or on asurface of a boundary portion of the structure member or inside thestructure member, to reinforce the structure member.

In the reinforced structures set forth in third and fourth aspects ofthe present invention, the reinforcing member may be fixed to thestructure member in such a manner that an effective constraint range ofthe reinforcing member covers the pre-calculated width and length of agap to be generated in the structure member in future.

The substrate may be made of at least one material selected from thegroup consisting of (1) concrete, (2) steel frame, (3) brick, (4) block,(5) gypsum board or plaster board, (6) wood, (7) rock, (8) earth orsoil, (9) sand, (10) resin and (11) metal.

The fixation may be performed by means of an adhesive. The layer of theadhesive applied to the reinforcing member or the structure member mayhave a thickness in the range of 5 to 90%, preferably 20 to 40%, of thethickness of the reinforcing member.

The fixation may be performed by placing the reinforcing member on thestructure member through the layer of the adhesive and then applying apressing force or a beating force to the reinforcing member whileallowing a part of the adhesive to be infiltrated into the reinforcingmember. In case of the woven body, the fixed portion of the reinforcingmember may have a void ratio of 1.1 or more. In case of the tape-shapedor sheet-shaped body, the fixed portion of the reinforcing member mayhave a void ratio of 1.4 or more.

The bonding strength of the fixation may be less than the peeling/shearfracture strength between the structure member and the reinforcingmember. This prevents the reinforcement effect from disappearing due tofracture in the structure member and the reinforcing member before theoccurrence of peeling in the fixed portion. Specifically, the bondingstrength may be in the range of 10 to 80% of peeling/shear fracturestrength in the surface of the structure member applied with theadhesive.

The adhesive may be a one-component, non-solvent adhesive.

The fixation of the reinforcing member to the structure member may beperformed without chamfering the structure member and adjusting theunevenness of the surface of the structure member.

In the reinforced structures set forth in third and fourth aspects ofthe present invention, even after the structure member has a gap, thereinforcing member holds or constrains the structure member in such amanner that it forms an envelope surface covering a surface of thestructure member adjacent to the gap to serve as a medium fortransmitting a stress acting on the structure member on both sides ofthe gap (bridge for transmitting the stress). The envelope surfaceserving as the transmission medium is formed by elongation in thereinforcing member adjacent to the gap and/or peeling in the fixedportion adjacent to the gap. In other words, the envelope surfaceserving as the transmission medium is formed by the elastic elongationof the reinforcing member in a free zone where the fixation is releaseddue to the generation of the gap.

The term “substrate” means a material constitutes a structure membersubject to reinforcement, and a physical object to which a reinforcingmember is to be fixed. The shape and material of the substrate areappropriately selected depending on a desired performance or function ofthe structure member. The material of the substrate is not limited to aspecific form or type, and may be any conventional structural material,any conventional non-structural material or any filler material. Forexample, the substrate may be concrete, steel frame, brick, block,gypsum or plaster board, precast concrete, wood, rock, earth or soil,sand, metal, or granular resin. The substrate may include plural kindsof materials. For example, when a filler material such as resin isfilled in a space between a structure member and a reinforcing member,the combination of the filler material and the material of the structuremember may be defined as the substrate. The term “gap” herein means achap or crack generated in a structure member. When a structure memberhas a deformation inducing a gap therein, the resulting displacementbetween the structure member and a reinforcing member adjacent to thegap forms an envelope surface in a portion of the reinforcing memberaround the gap of the structure member without any fracture of thereinforcing member. The enveloped surface serves as a bridge allowing astress of the structure member to be transmitted across the gap. Thatis, a shear stress is transmitted through the boundary surface betweenthe reinforcing member and a portion of the structure member having nogap or through a fixed portion. The envelope surface of the reinforcingmember is formed based on a plurality of factors including as theelongation of the reinforcing member adjacent to the gap, the release(peeling-or another factor) of the fixation adjacent to the gap, and thefixation around the gap.

The fixation of a reinforcing member to a structure member is performedby applying an adhesive a part or all of the boundary surface betweenthe structure member and the reinforcing member, or by closingly loopinga reinforcing members in an adhesive or mechanical manner whileenclosing and deforming a portion of the structure member, so as toprovide a tensile force in the reinforcing members to generate africtional or bearing force between the reinforcing member and thestructure members.

The adhesive to be applied to the boundary between a structure memberand a reinforcing member is required to maintain an adhesion strengthrequired for fixing the reinforcing member to the structure member, forthe period of use of the structure member under environmental conditionsof the structure member. In this case, there is no need to set therequired adhesion strength at a value higher than the fracture strengthof the structure member or the reinforcing member. Thus, the adhesivemay be one-component adhesive. The adhesive may also be applied to thereinforcing member in advance, and stored together with the reinforcingmember. In this case, an operation of fixing the reinforcing member canbe quickly completed.

The term “fixation zone” herein means a zone where the reinforcingmember is fixed. The term “free zone” means a zone where the fixation ofthe reinforcing member is released (due to peeling or another factor).In an after-mentioned design method, the ratio of the size of thefixation zone to the size of the free zone is expressed by a numericalvalue of “constraint ratio”.

The terms “fixation strength” and “fixation range” herein mean astrength and a range capable of causing the displacement in a specificfinite areas (free zone) of reinforcing and structure members when thestructure member has a local fracture inducing a gap, so as to allow astress of the structure member to be transmitted through the reinforcingmember across the gap without any fracture of the reinforcing member.

The relationship between load and deformation of the structure memberafter the generation of the gap is expressed as the functions of thedimensions of the structure member, the boundary condition of thestructure member, the position and size of the gap, the Young's modulusand thickness of the reinforcing member, and the size of a free zonecaused by the gap. Thus, a required strength, required Young's modulus,required amount (required installation range, required thickness etc.)and required fixation strength of the reinforcing member can becalculated based on a value in a limit state (tolerance or thresholdvalue) of the size (width etc.) of a gap to be generated in thestructure member, the size of a zone where the elongation of thereinforcing member can be neglected (fixation zone), and the size of azone where the reinforcing member is to be elongated (free zone).

A Young's modulus for use in the calculation of the required amount etc.of the reinforcing member is a value (limit state value) correspondingto a strain to be generated in the reinforcing member in a limit statewhere the size of the gap reaches the threshold value. Therefore, inview of the elastic property of the reinforcing member, the design ofsetting a Young's modulus in the limit state to be greater than aYoung's modulus corresponding to another strain such as a strainimmediately before fracture can advantageously reduce the reinforcementamount.

The installation range of the reinforcing member is not necessarily theentire surface of the structure member, but may be a portion of thestructure member. In this case, the reinforcing member is installed toform an envelope surface in the circumferential direction of thestructure member or to form a surface capable of being in contact withthe portion of the surface of the structure member smoothly from theoutside.

The installation range of the reinforcing member is selectivelydetermined depending on a desired performance, shape or configuration ofa structure member, or a method of fixing a reinforcing member. Forexample, if a plurality of structure members are located adjacent toeach other, the reinforcing member may be installed such that anenvelope surface is formed to cover the junction between the adjacentstructure members, or it is penetratingly inserted into a hole or slitformed in the adjacent structure members. Further, if the structuremember is a flat member such as a wall, a reinforcing member may beinstalled on only one of the opposite surfaces thereof, or a reinforcingmember may be installed on the respective opposite surfaces thereof andclosingly looped through a through-hole formed in the structure member.

The aforementioned reinforced structure may be formed by providing areinforcing member to a structure member of an existing structural body,or may be formed by installing a reinforcing member to a structuremember of a structural body to be newly constructed. When the reinforcedstructure is applied to a new structural body, the size and weight ofthe structure member can be reduced as compared to the conventionaltechniques to provide reduced seismic load. This makes it possible toachieve drastically reduced construction cost of the structural body,and significantly enlarged utilizable space of a living room or thelike.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a structure member 1 with a reinforcingmember 5.

FIG. 2 is a sectional view taken along line A-A of FIG. 1.

FIG. 3 is a perspective view of a structure member 1 with a reinforcingmember 5.

FIG. 4 is a perspective view of a structure member 1 with a reinforcingmember 5.

FIG. 5 is a graph showing the relationship between load and deformationin a structure member 1.

FIG. 6 is a graph showing the relationship between circumferentialstrain and deformation in a structure member 1.

FIG. 7 is a perspective view of a structure member divided by a gap.

FIG. 8 is a sectional perspective view of a structure member slicedperpendicular to the axis thereof in FIG. 7.

FIG. 9 is a graph showing a stress-stain relationship of a reinforcingmember.

FIG. 10 is a graph showing the relationship between load and deformationin a non-reinforced model column.

FIG. 11 is a graph showing the relationship between load and deformationin a SRF-reinforced model column.

FIG. 12 is a graph showing the relationship peak load in a normaldirection and deformation.

FIG. 13 is a graph showing the relationship elongation strain in thecircumferential length of a structure member and deformation.

FIG. 14 is a perspective view of a wall-mounted column with areinforcing member.

FIG. 15 is a sectional view of the wall-mounted column in FIG. 14.

FIG. 16 is a sectional view of the wall-mounted column in FIG. 14.

FIG. 17 is a perspective view of an H-section structure member 143 afterreinforcement.

FIG. 18 is a perspective view of a hollow structure member 149 afterreinforcement.

FIG. 19 is a partial sectional view of a reinforced member 181.

FIG. 20 is a graph showing the relationship between load and deformationwith respect to the member 181.

FIG. 21 is a plan view of a polyester belt 199.

FIG. 22 is a perspective view showing an example of a column 205reinforced by use of a beltlike reinforcement 201.

FIG. 23 is a perspective view showing an example of a column 205reinforced by use of a beltlike reinforcement 201.

FIG. 24 an elevation of the column 205 shown in FIG. 23.

FIG. 25 is a sectional view of a surface portion of the column 205 shownin FIGS. 22 to 24.

FIG. 26 is a view showing an effective bond length between the beltlikereinforcement 201 and a crack 215.

FIG. 27 is a schematic view of the column 205 subjected to an axialforce, bending, and a shear force.

FIG. 28 is a view showing a force which attempts to expand the crack 215formed in the column 205.

FIG. 29 is a view showing the deformation of the column 205.

FIG. 30 is a view showing horizontal force Q applied to the column 205and an envelope indicative of displacement hysteresis of the column 205.

FIG. 31 is a view showing the relationship among the horizontaldisplacement of the column 205, the vertical displacement of the column205, and a horizontal force applied to the column 205.

FIG. 32 is a view showing restoring-force characteristics of the column205.

FIG. 33 is a view showing the relationship between cumulative horizontaldisplacement Σδ_(h) and hysteretic absorbed energy W in the column 205.

FIG. 34 is a detailed view of FIG. 33.

FIG. 35 is a view showing the relationship between cumulative horizontaldisplacement Σδ_(h) and vertical displacement δ_(v).

FIG. 36 is a perspective view showing a state in which connectingreinforcements 269 a and 269 b are disposed on the joint between acolumn 261 and a beam 263.

FIG. 37 is a perspective view showing a state in which a beltlikereinforcements 271 a and 271 b are disposed on the joint between thecolumn 261 and the beam 263.

FIG. 38 is a sectional view of the joint between the column 261 and thebeam 263 on which the connecting reinforcements 269 b, etc. aredisposed.

FIG. 39 is a design flowchart for determining the amount ofreinforcement.

FIG. 40 is a design flowchart for determining the amount ofreinforcement.

FIG. 41 is a diagram showing the relationship between cumulativedeformation and hysteretic absorbed energy with respect to a reinforcedmember.

FIG. 42 is a diagram showing the relationship between tensile stress andstrain with respect to a reinforcement material impregnated with resinand a reinforcement material unimpregnated with resin.

FIG. 43 is a diagram showing properties (test specifications) of thetested columns, loading conditions, test results, and SRF reinforcementeffects etc.

FIG. 44 is an explanatory diagram of the relationship between the widthof a gap and the elongation of a reinforcing member.

FIG. 43 is a diagram showing the relationship between the tensile forceof a reinforcing member and the relative displacement of a structuremember in a SRF-reinforced structure.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference to the drawings, various embodiment of the presentinvention will now be described in detail.

FIG. 1 is a perspective view of a structure member (or a member of astructural body) with a reinforcement member according to an embodimentof the present invention. FIG. 2 is a sectional view taken along theline A-A in FIG. 1. As shown in FIGS. I to 3, a structure member 1comprises a substrate 3 with a reinforcing member 5. The reinforcingmember 5 is installed, for example, in such a manner that it envelops aportion of the surface of the substrate 3 (see FIG. 1), or it encloses agiven portion (periphery etc.) of the substrate (FIG. 3). The substrate3 is principally a material constituting the structure member 1 subjectto reinforcement, and a physical object to which the reinforcing member5 is to be fixed. The shape and material of the substrate 3 areappropriately selected depending on a desired performance or function ofthe structure member 1. The substrate 3 is a structural material such asreinforced concrete, a non-structural material such as block or brick,or a filler material such as sand or granular resin. The reinforcingmember 5 installed on the surface the substrate 3 acts to bear a stressof the substrate 3 while bridging between both sides of a fracturedsurface such as chap or crack (or gap) generated in the substrate.

In addition to the above function, a reinforcing member 5 according to afirst mode of embodiment is composed of a woven body having all ofextensibility (high ductility and high bendability), strength andelasticity, and adapted to be installed on the surface of or inside asubstrate of a structural body to reinforce the substrate. The wovenbody characteristically has a Young's modulus equal to or less than thatof the structure member (substrate), and a tensile fracture strain of10% or more.

When the structure member includes plural kinds of primary substrates(materials), the term “Young's modulus of the structure member(substrate)” herein means the lowest one in the respective Young'smoduluses of the materials.

As above, the reinforcing member has high ductility and highbendability, or extensibility. The term “high ductility” means to have alarge fracture strain. The term “high bendability” means to readilycause a large bending deformation and shear deformation (highflexibility) without fracture.

Even if a substrate is deformed to have a gap or irregular surface, thereinforcing member having high ductility can constrain the substratewithout fracture to maintain a desired reinforcement effect.

The reinforcing member having high bendability can be readily bent at anacute angle. Thus, the reinforcement can be installed along an irregularcircumferential surface of a structure member, and can be deformed underload to have a fixed portion formed in conformity to the curvature orcorner angle of a substrate.

The reinforcing member is required to have elasticity for generating atensile force in response to change in the circumferential length of asubstrate to bring out a geometrical constraint effect and coping with arepeated alternate load or the like. Preferably, the rigidity of thereinforcing member is greater at the initial stage of the generation ofstrain than immediately before fracture.

In the present invention, the Young's modulus of the woven bodyconstituting the reinforcing member 5 is set to be equal to or less thatthat of the structure member. This is intended to reduce a stress actingon the boundary surface the reinforcing member and the substrate 3 whenthe reinforcing member starts deforming in response to the occurrence ofdeformation or crack in the structure member 1 due to a load acting onthe substrate 3, so as to increase a limit deformation causing peelingin the boundary surface. Further, the tensile fracture strain of thewoven body is set at 10% or more. Because in the design of structuralbodies for an accidental load due to earthquake or the like, a designlimit is generally about 2 to 4% of deformation in a structure member.Additionally considering a local-strain-concentration coefficient of 5,the reinforcing member would be not fractured in the design limit if thefracture strain is 10% or more. According to the results of loadingtests of a structure member, in case where a reinforcing memberincluding aramid fibers having several % of fracture strain was bondedon a surface of a structure member, the fracture of the reinforcingmember was observed. On the other hand, in case where the structuremember was reinforced by a SRF reinforcing member having 10% or more offracture strain, no fracture was observed in the reinforcing member

By contrast, in the reinforcing member disclosed in the aforementionedJapanese Patent Laid-Open Publication No. 8-260715, the Young's modulusand fracture strain of aromatic polyamide fibers used therein aredirectly applicable. Thus, the Young's modulus is in the range of 80000to 120000 MPa, and the tensile fracture strain is in the range of 2.5 to4.5%. Further, when the aromatic polyamide fibers act as an actualreinforcing member, it will be an aromatic-polyamide-fiber-reinforcedepoxy resin having higher bending and shear rigidities than those of theelemental fibers. As a result, the reinforcing member is likely to peeloff over a wide range at the same time due to inability of following thedeformation of a substrate. In this connection, the Young's modulus ofconcrete is about 20000 MPa, and the Young's modulus of hard wood suchas oak is about 10000 MPa.

The Young's modulus of the woven body is preferably in the range of 1/2to 1/20, more preferably 1/5 to 1/10, of that of the substrate. If theYoung's modulus is less than the lower limit of the range (or the valueof Young's modulus is excessively small), the reinforcing member has tobe designed to have an increased thickness to obtain a desiredreinforcement amount. This is economically inefficient. Further, asdescribed later, a peeling-limit elongation (δ1: FIGS. 44 and 45) isincreased, resulting in delayed response of the reinforcement effect andincreased damage of the structure member.

Specifically, the Young's modulus of the reinforcing member ispreferably in the range of about 500 to 5000 MPa, more preferably about1000 to 1000 MPa.

Preferably, the tensile fracture strength of the woven body is in therange of 3 to 5 times of that of the structure member. Any localfracture of the structure member can be avoided by setting a stressconcentration coefficient in the range of 3 to 5.

The thickness of the woven body is preferably in the range of 0.2 to 20mm, more preferably 0.5 to 15 mm, particularly 1 to 10 mm. This range isdesired to obtain an intended performance and facilitate handling.

Preferably, the material of strings constituting the woven body ispolyester (fiber).

Preferably, the woven body has a bending deformation angle of 90-degreeor more, and a shear deformation angle of 2-degree or more.

Preferably, the woven body is heat-set to allow a Young's modulus in alimit state to be greater than a Young's modulus immediately beforefracture.

Preferably, the reinforcing member has an elongation strain in the rangeof 0.1% to 10% in the limit state.

A reinforcing member according to a second mode of embodiment is atape-shape or sheet-shaped body made of a rubber-based or resin-basedelastic material, and adapted to be installed on a surface of or insidea substrate of a structural body to reinforce the substrate. Further,the tape-shaped or sheet-shaped body has a Young's modulus equal to orless than that of the structure member, and a tensile fracture strain of10% or more.

The Young's modulus of the tape-shaped or sheet-shaped body ispreferably in the range of 1/2 to 1/20, more preferably 1/5 to 1/10, ofthat of the substrate. Specifically, the Young's modulus of thereinforcing member composed of the tape-shaped or sheet-shaped body isalso preferably in the range of about 500 to 5000 MPa, more preferablyabout 1000 to 1000 MPa.

The thickness of the tape-shaped or sheet-shaped body is preferably inthe range of 0.2 to 20 mm, more preferably 0.5 to 15 mm, particularly 1to 10 mm.

Preferably, the tape-shaped or sheet-shaped body has a bendingdeformation angle of 90-degree or more, and a shear deformation angle of2-degree or more.

The above factors of the reinforcing member according to the second modeof embodiment have been selectively determined in the same way as thatin the reinforcing member according to the first mode of embodiment.

Two types of reinforced structures for a structural body according tothird and fourth modes embodiment of the present invention comprise thereinforcing members according to the first and second modes ofembodiment, respectively. Further, the reinforcing member is fixed on asurface of or inside a substrate constituting a structure member andincluding at least one material to reinforce the substrate.

In the reinforced structures, the reinforcing member is preferably fixedto the substrate in such a manner that an effective constraint range ofthe reinforcing member covers the pre-calculated width and length of agap to be generated in the substrate in future.

In other words, the reinforcing member 5 is fixed to the substrate 3 inthe structure member 1. More specifically, the reinforcing member 5 andthe substrate 3 are constrained to one another. The mechanism of thisconstraint is roughly classified into two types. A first mechanism is abonding constraint, and a second mechanism is a geometrical constraint.

The first mechanism or bonding constraint is achieved by bonding thereinforcing member 5 to the substrate 3. In this case, even after a gapis generate to create a zone where the bond is separate (herein afterreferred to as “free zone”), as long as a bonded portion exists aroundthe free zone, the bonding constraint can be maintained.

The thickness of the layer of an adhesive applied to the reinforcingmember or the substrate is preferably in the range of 5 to 90%, morepreferably 20 to 40%, of the thickness of the reinforcing member.

The fixation is performed by placing the reinforcing member on thesubstrate through the layer of the adhesive and then applying a pressingforce or a beating force to the reinforcing member while allowing a partof the adhesive to be infiltrated into the reinforcing member. In caseof the woven body, the fixed portion of the reinforcing memberpreferably has a void ratio of 1.1 or more. In case of the tape-shapedor sheet-shaped body, the fixed portion of the reinforcing memberpreferably has a void ratio of 1.4 or more. In this way, gas generatedduring the curing reaction of the adhesive can be adequately releasedfrom the adhesive layer or the reinforcing member. Thus, an initialbonding ability can be achieved without generation of gas bubbles in theadhesive layer, defective bonding, and swollenness and float of theadhesive layer. The upper limit of the void ratio is not limited to aspecific value, but preferably in the range of about 2 to 3.

Preferably, the bonding strength is less than the strength of thesubstrate. If the bonding strength is equal to or greater than thestrength of the substrate, the fracture of the structure member causesthe generation of a tensile force in the reinforcing member and therelease of the bonding to annul the reinforcement effect in a wide rangeat the same time. The bonding strength is preferably in the range of 10to 80% of peeling/shear fracture strength in the surface of thesubstrate applied with the adhesive. If the bonding strength is higherthan the upper limit of the range, the structure member will be damagedin an operation of detaching the reinforcement. If the bonding strengthis lower than the lower limit of the range, a desired reinforcementeffect cannot be obtained. Specifically, the bonding strength ispreferably in the range of about 1 to 2 N/mm². In this connection, thepeeling/shear fracture strength of concrete is about in the range of 3to 5 N/mm².

By contrast, in the reinforcing member disclosed in the aforementionedJapanese Patent Laid-Open Publication No. 8-260715, the epoxy resin tobe impregnated also serves as an adhesive. Thus, if a structural bodymade of concrete is reinforced by this reinforcing member, the bondingstrength will become higher than the strength of the substrate to causethe aforementioned problems.

While any suitable adhesive satisfying the above condition may be used,the adhesive is preferably a one-component, non-solvent adhesive. Thisone-component, non-solvent adhesive may include an epoxy-urethane-based,non-solvent, moisture-setting type adhesive. This type of adhesiveadvantageously has no odor, no open time and long lifetime.

The fixation of the reinforcing member to the structure member or thesubstrate can be performed without chamfering the structure member orthe substrate and adjusting the unevenness of the surface of thestructure member or the substrate. By contrast, in the reinforcingmember disclosed in the aforementioned Japanese Patent Laid-OpenPublication No. 8-260715, it is practically required to chamfer thesubstrate at R=10 mm or more due to aramid fibers as a primary componentof the reinforcing member. If carbon fibers are used, R=20 mm or more ofchamfering will be required.

In the reinforced structures according to the third and fourth modes ofembodiment, the fixation can be achieved without the large bondingstrength as described above. Thus, there is no need for any primertreatment and any anchoring operation after the fixation. For example,only by winding the reinforcing member around the structure member, evenafter peeling, the reinforcement effect can be maintained by thegeometrical constraint.

The adhesive 11 may be applied to the reinforcing member 5 at a workingsite of the bonding operation. Alternatively, the adhesive 11 may beapplied to the reinforcing member 5 in advance, and stored until thebonding operation. In these reinforced structures, in an operation ofdetaching or peeling the adhesive, the substrate 3 or the reinforcingmember is never damaged while leaving the adhesive layer thereon.

When it is required to achieve the bonding constraint, as shown in FIG.1, the reinforcing member 5 is installed in a range (reinforcing-memberinstallation range 9) extending outward from a range (effective bondingconstraint range 7) for reinforcing the structure member 1. Theeffective bonding constraint range 7 is selectively determined dependingon a required performance or function of the structure member 1. Theeffective bonding constraint range 7 may be a portion of the surface ofthe structure member 1. In this case, the reinforcing member 5 isinstalled to form an envelope surface in the circumferential directionof the structure member 1 or to form a surface capable of being incontact with the portion of the surface of the structure member smoothlyfrom the outside.

The second mechanism or geometrical constraint is achieved, for example,by bonding both ends of a reinforcing member and installing thereinforcing member in such a manner that it encloses a given portion(periphery etc.) of a substrate 3, as shown in FIG. 3. In this case, thesubstrate 3 and the reinforcing member 5 is geometrically connectedtogether, and constrained to one another.

More specifically, in conjunction with the deformation of the substrate,the length of the closed or looped reinforcing member is changed togenerate a tensile force in the reinforcing member. If the reinforcingmember is installed in conformity to the curvature or corner angle ofthe substrate, the tensile force will cause the frictional force orbearing force between the reinforcing member and the substrate so thatthe substrate and the reinforcing member exert a constraint forceagainst deformation to one another. In case where a reinforcing memberis bonded in conformity with the corner angle of a substrate, it can beexpected to have a geometrical constraint-like effect such that thebearing force of the bonded surface at the corner is increased by thetensile force of the reinforcing member to provide enhanced bondingstrength.

While the geometrical constraint is changed depending on the shape ofthe substrate 3, the relative positional relationship between thereinforcing member 5 and the substrate 3, it can be maintained until thereinforcing member 5 is fractured even if the substrate 3 is fractured.On the other hand, the bonding constraint disappears when the substrate3 is fractured, and the bonding strength becomes lower than a givenvalue as described later.

The quantification of the effect of the reinforcing member(reinforcement effect model) will be described below. FIG. 4 is aperspective view showing a portion of a structure member 1 having thereinforcing member 5 installed thereon, wherein the reinforcing member 5elastically constrains a substrate 3 having a gap 13. The gap is a crackor chap generated in the substrate 3. A gap width 15 (d) means the widthof the gap 13.

Upon deformation of the structure member 1, a stress is concentrated onthe reinforcing member and the surface of the structure member 1adjacent to the gap 13 to cause the peeling of the reinforcing member 5from the surface of the structure member 1. In the followingdescription, this peeled area is referred to as “free zone 19”, and thelength of the free zone 19 associated with the region having a width 23(Δw) of the reinforcing member 5 is referred to as “free length (a)”. Inthe area where the bonding or geometrical constraint is achieved, thereinforcing member 5 and the structure member are constrained to oneanother.

In the following description, this constrained area is referred to as“constraint zone 21”, and the length of the constraint zone 21associated with the region having the width 23 (Δw) of the reinforcingmember 5 is referred to as “constraint length (a)”. When a free zone isgenerated, a fixation length (s) is reduced from a constraint length (b)by a factor of a free length (a). In this case, a certain shear force,such as a bonding or frictional force, acts between the reinforcingmember 5 and the substrate 3 in a zone (fixation zone) of the fixationlength (s=b−a). While it can be technically said that the constrainedarea is enlarged as the free length is increased, this hypothesis willbe ignored in the following calculation in view of a risk-freeapproximate calculation.

Given that in a portion of the reinforcing member 5 of the width 23(Δw)×the constrained zone 21 (constrained length (b)), an average valueof shear stresses 18 acting between the surface of the substrate 3 andthe non-peeled reinforcing member 5 is Tf, and a tensile force, Young'smodulus and thickness in the free zone 19 of the reinforcing member 5being q, E_(f) and t, respectively. The tensile force 17 and theresultant of the shear stresses 18 are balanced in the fixation zone,and thus the following relational expression is formulated. In thefollowing relational expression, the reinforcing member is presupposedas an elastic body, and the elongation in the region of the fixationlength is ignored because it is small as compared to the elongation inthe free zone. $\begin{matrix}{q = {\frac{{dE}_{f}t\quad\Delta\quad w}{a} = {\left( {b - a} \right)\tau_{f}\Delta\quad w}}} & \lbrack 1\rbrack\end{matrix}$

The following relational expression can be obtained by eliminating “a”from the expression [1], dividing by tΔw, and giving that a tensilestress of the reinforcing member 5 is σ_(f). $\begin{matrix}{{\sigma_{f}^{2} - {\frac{b}{t}\tau_{f}\sigma_{f}} + {\frac{d}{t}E_{f}\tau_{f}}} = 0} & \lbrack 2\rbrack\end{matrix}$

From the condition of the real root of σ_(f), it can be proved that agap width d is between 0 (zero) and $\begin{matrix}{d_{\max} = {\frac{b^{2}\tau_{f}}{4E_{f}t}.}} & \lbrack 3\rbrack\end{matrix}$

For a certain gap width d, two of σ_(f) will be derived as a solution.Given that larger one of them is achieved, a maximum value σ_(fmax) anda minimum value σ_(fmin) of σ_(f) are expressed as follows:$\begin{matrix}{{\sigma_{f\quad\max} = {\frac{b}{t}\tau_{f}}},\quad{\sigma_{f\quad\min} = {0.5\quad\sigma_{f\quad\max}}}} & \lbrack 4\rbrack\end{matrix}$

σ_(fmax) is a stress in the condition of the gap width d=0 or at thetime when the gap 13 is just generated on the surface of the structuremember 1. σ_(fmin) is a stress at the time when the gap 13 is enlarged,and the gap width d reaches a value d_(max) in the expression [3].According to the expressions [1] to [3], when the tensile stress of thereinforcing member 5 is σ_(fmin), the free length (a) is calculated as ½of the constraint length (b). If the gap width d is increased at a valuelarger than dmax, the expression [1] will be invalid in view ofdynamical theories, the free length (a) will be sharply increased untila certain constraint such as geometrical constraint is given again.

The change in the length (hereinafter referred to as “circumferentiallength”) L of the envelope (the circumference of the envelope surface)can be presupposed as the change in the total value d of the gap widthacross the circumference. Thus, the following formula is satisfiedbetween a circumferential strain φ and the total value of the gap widthmeasured along the circumference. In the following formula, L₀ is thecircumferential length before the generation of the gap.d=φL₀   [5]

Further, given that the reinforcing member 5 is elongated only in thefree zone (free length a) where the fixation between the reinforcingmember 5 and the structure member 1 is separated, the followingrelational expression of the circumferential strain φ and the strainE_(f) of the reinforcing member by focusing on the elongation of thereinforcing member 5 installed to form the envelope surface:$\begin{matrix}{\frac{a}{L_{0}} = \frac{\Phi}{ɛ_{f}}} & \lbrack 6\rbrack\end{matrix}$wherein a/L₀ is an index indicating the level of the constraint, andthus hereinafter referred to as “constraint rate”.

The tensile force 17 (σ_(f)) of the reinforcing member 5 can becalculated as follows in accordance with the strain (ε_(f)) and Young'smodulus (E_(f)) of the reinforcing member 5. In the following formula, asecant Young's modulus will be used if the Young's modulus of thereinforcing member is changed dependent on the strain thereof.σ_(f)=ε_(f)E_(f)   [7]

Given that after the structure member 1 is fractured by the action ofrepeated load, it can be approximated as a granular body, the followingrelational expression is satisfied: $\begin{matrix}{\sigma_{f} = {\frac{B}{2t}\sigma_{3}}} & \lbrack 8\rbrack\end{matrix}$wherein B is the distance (sectional width) between the reinforcingmembers, and σ₃ is a constraint pressure of the granular body.

The following relational expression can be obtained by applying therelationship between the primary stress σ_(f) and constraint pressure σ₃of the granular body to the expression [8]: $\begin{matrix}{\sigma_{f} = {\frac{B\left( {1 - {\sin\quad\varphi}} \right)}{2{t\left( {1 + {\sin\quad\varphi}} \right)}}\sigma_{1}}} & \lbrack 9\rbrack\end{matrix}$

In the state of axial compression, the value of the primary stress s₁can be approximated as a value derived from dividing a compressive forceby a pressure-receiving sectional-area. On the other hand, under thecondition of receiving a shear force, it is required to calculate withthe inclusion of the influence of the shear force.

The relationship of the tensile force of the reinforcing member, thedeformation causing a gap of the structure member and the fixation forceis obtained from the expressions [3] to [7] and [9]. Further, since thedeformation causing a gap would represent the level of the damage of thesubstrate, the relationship between the damage of the substrate and thetensile force (or strain) of the reinforcing member can also beobtained.

The above model is unconfined by the type of the gap 13. Specifically,the model is applicable to any gap 13 caused by any factor including adynamical factor, such as bending or shear, and a material factor, suchas temperature, dryness, expansion or deterioration. According to themodel, particularly when the reinforcing member 5 is installed in adirection crossing to a gap 13 caused by shear (shear chap, shearfracture surface, etc.), it can elastically constrain the surrounding ofthe gap 13 to control a shear deformation at a finite value and maintainthe toughness of the structure member 1.

Further, the above model is unconfined by the type of the substrate 3.The substrate 3 may be any construction material, such as reinforcedconcrete, steel framed reinforced concrete, steel frame, brick, block,gypsum or plaster board, precast concrete product, wood, rock, sand orresin. The substrate 3 may be an existing structural or non-structuralmartial or a newly installed material.

The installation of the reinforcing member 5 may be a portion of thestructure member as long as it is wider than an area (effective bondingconstraint range 7) corresponding to the constraint zone 21 (constraintlength (b)) for the crack or gap 13. Referring to FIG. 1, the area ofthe effective bonding constraint range 7 in the reinforcing-materialinstallation range 9 is an effective range.

According to the expressions [3] and [4], the reinforcement effect issuperficially increased in proportion to the bonding strength. However,if the bonding strength is set at a value close to the full strength ofthe substrate 3 or the reinforcing member 5, the substrate 3 or thereinforcing member 5 will be locally fractured before generation of afree length (a) to annul the reinforcement effect. Thus, the bondingstrength is required to be set at a level causing no fracture in thesubstrate 3 and the reinforcing member 5 in the above process.

The aforementioned model can be achieved if the reinforcing member 5 isnot fractured by a stress concentration arising around a crack or gap orat a corner of the structure member 1 in connection with the generationand enlargement of the gap 1 in the structure member 1. Thus, it is alsorequired to provide extensibility (large fracture strain) to thereinforcing member 5. While carbon fibers or aramid fibers have a largeelastic coefficient and fracture strength, any material having a smallfracture strain is not suitable as the reinforcing member in the firstmode of embodiment and another after-mentioned mode of embodiment.

The model can also be achieved if the reinforcing member brings out asufficient performance even after the adhesive layer between thesubstrate and the reinforcing member is partly fractured. Thus, acontinuous-fiber reinforcing member whose performance is defined underthe condition of a structure in which a a shear yield strength isincreased as the deformation of the structure member is increased.Therefore, a shear load-deformation relationship has two extreme values,as described later in conjunction with FIGS. 5, 12, etc.

FIG. 5 is a graph schematically showing the above relationship betweenload and deformation. The horizontal axis represents a deformation(deformation angle) in a structure member 1, and the horizontal axisrepresents a load acting on the structure member 1. The shape of thecurve is described by ten parameters or Q_(max1), α Q_(max), Q_(mid),Q_(min), Q_(max2) and R₁ to R₅. Q_(max1) is an initial maximum vale ofthe load, α Q_(max) being the load in a limit state (design ultimatestate etc.), Q_(min) being a minimum value of the load, Q_(mid) beingthe load by which the bonding constraint is released and shifted to thegeometrical constraint, and Q_(max2) being the load by which thereinforcing member 5 is fractured, or the deformation of the structuremember 1 reaches at an extreme value and becomes unable to bear anyload. R₁ to R₅ are the deformations corresponding to Q_(max1), αQ_(max), Q_(mid), Q_(min), Q_(max2), respectively. The limiting point 27(Q_(min), R₄) is a point where the structure member 1 is fractured byload, and starts exhibiting behaviors of a granular body.

FIG. 6 is a graph showing the relationship between circumferentialstrain and deformation in the structure member. The horizontal axisrepresents a deformation (deformation angle) in the structure member 1,and the horizontal axis represents a circumferential strain in thestructure member 1. The change in an apparent volume, or a volumeassociated with an envelope surface, of the structure member 1 isexpressed by a circumferential strain (strain in the circumferentiallength of the section of the structure member 1 in a directionperpendicular to the axis thereof and an axial strain (strain in theaxis of the structure member 1). The circumferential strain φ is changedas shown in the graph 29 in response to the carbon or another fibersbound by resin are bonded on the surface of a substrate without floatand wrinkle is not suitable as the reinforcing member in the first modeof embodiment and another after-mentioned mode of embodiment.

Further, the reinforcing member 5 is also required to have elasticity tobring out a control effect to the phenomenon that the gap 13 is openedand closed by a repeated alternate load.

The quantification of the performance of a structure member 1(structure-member performance model) will be described below. Thedynamic performance and durability of the structure member can bequantified in consideration of the performance of a substrate and adesired reinforcement effect. The following description will be made inconjunction with one example in which a substrate 3 of the structuremember 1 is a bar-shaped member made of reinforced concrete, and thesubstrate 3 is reinforced by the reinforcing member 5 and subjected torepeated shear.

As mentioned in connection with the reinforcement effect model, evenafter a shear gap is generated in a structure member 1 due to a repeatedshear force applied thereto, a shear force will be transmitted throughthe reinforcing member 5 across the gap to cause a bending deformationand maintain the toughness of the structure member 1. The reaction forceof the reinforcing member 5 is borne by the bonding constraint until thetensile force of the reinforcing member 5 is increased up to σ_(fmin) inthe expression [4], and subsequently borne by the geometricallyconstraint.

Then, when the substrate 3 is increasingly fractured by the work ofrepeated load action to have dynamic characteristics such that they canbe approximated as those of a granular body (dense sands) having asurface covered by an elastic body, change of the relationship betweenthe load and the deformation in FIG. 5.

(R₁, φ₁), (R₂, φ₂), (R₃, φ₃), (R₄, φ₄) and (R₅, φ₅) in FIG. 6 correspond(R₁, Q_(max1)), (R₂, α Q_(max)), (R₃, Q_(mid)), (R₄, Q_(min)) and (R₅,Q_(max2)), respectively.

The circumferential strain is gradually increased as the bonding isseparated to increase a free zone 19. In the range of R₃ to R₄, thecircumferential strain is kept approximately constant by the geometricalconstraint. When the deformation goes beyond R₄, the circumferentialstrain will be increased again because the structure member 1 behaves asa granular body. The axial strain is changed in the same manner as thatof the circumferential strain.

The result of an experimental verification will be described below.While the structure member is described as a column in the followingdescription, it is not limited to such a column.

FIG. 7 shows the state when a region having the width 39 (H) of astructure member 31 reinforced by a reinforcing member 37 is dividedinto a first segmental member 33 a second segmental member 35 by astructural gap 41 (gap width 43 (d)), and the opposite ends of thedivided structure member receive the action of a shear force 45 (Q). Thereinforcing member 37 is installed to form an envelope surface in thecircumferential direction of the structure member 31 or to form asurface capable of being in contact with the portion of the surface ofthe structure member smoothly from the outside. The shear force 45 isbeing transmitted between the first and second segmental members 33, 35through the reinforcing member 37 in each section.

FIG. 8 is a perspective view of the section (thickness 47 (ΔH))perpendicular to the axis of the structure member in FIG. 7. Each ofshear forces, reinforcing-member tensile stresses 51 (σ_(f)), andtensile forces 53 (σ_(cs)) of concrete from the shear force 45(Q). Giventhat the Young's modulus of the reinforcing member 37 is E_(f), areinforcing-member strain ε_(f) can be expressed by the followingexpression. $\begin{matrix}{ɛ_{f} = {\frac{\sigma_{f}}{E_{f}} = \frac{Q_{f}}{2E_{f}{Ht}}}} & \lbrack 11\rbrack\end{matrix}$

The result of an experimental test on the effect of the abovereinforcing member, and the performance of a structure member having thereinforcing member installed thereon will be described below. The testwas carried out using an RC column (SRF-reinforced model column) havingthe above reinforcing member installed thereon and a non-reinforced RCcolumn (non-reinforced model column) (SRF: Soft Retrofitting forFailure). The outline of the test is shown as follows.

An axial force and a repeated shear force are applied to the columnwhile constraining the rotation of the capital and base of the column.

A horizontal force is applied to the capital through a rigid framehaving a loading point at the center of the column.

Under a displacement control, deformation angles of 1/400 to 4/400 areapplied in the positive and negative displacements two times, and thendeformation angles of 6/400, 8/400, 16/400, 24/400, 32/400, 48/400 and64/400 are applied in the positive and negative displacements one time,and finally, a deformation angle of 200/900 as a limit of a pressuredevice is applied.

Fourteen cases were tested under a variable axial force and a constantaxial force. Among these cases, the results of nine cases under aconstant axial force were used to quantitatively evaluate theperformance of the above SRF reinforcing member. and reinforcing baracts on the structure member 31 (first and second segmental members 33,35) and the reinforcing member 37. Among the shear forces, a first shearforce to be transmitted from the upper surface of the first segmentalmember 33 to the lower surface of the second segmental member 35 throughthe reinforcing member 37 is defined as a transmission shear force 49(ΔQ_(f)). While not shown, there is a second shear force to betransmitted in the opposite direction of the first shear force or fromthe upper surface of the second segmental member 35 to the lower surfaceof the first segmental member 33 at the same value as that of the firstshear force.

Given that the tensile force 53 (σ_(cs)) is 0 (zero) for the purpose ofsimplifying the description without losing universality, the differencebetween the shear forces in the upper and lower surfaces of the firstsegmental member 33 provides the transmission shear force 49 (ΔQ_(f)).The same goes for the second segmental member 35.

Given that the thickness 47 (ΔH) is infinitely small, and a body forceand a moment with an arm having a length in the thickness direction areignored. Further, given that there is no distributed load, and thereinforcing member 37 bears only the tensile stress 51 for the purposeof simplicity. Furthermore, given that the transmission shear force 49(ΔQ_(f)) acts to the reinforcing member 37 such that the front-side andback-side tensile stresses 51 (σ_(f)) become equal to each other, andΔQ/ΔH is constant, the following relation is satisfied in view of abalance expression: $\begin{matrix}{\sigma_{f} = \frac{Q_{f}}{2H_{t}}} & \lbrack 10\rbrack\end{matrix}$wherein t is the thickness of the reinforcing member 37, and Q_(f) is avalue derived by eliminating the shear forces transmitted throughconcrete and reinforcing bar

FIG. 43 is a chart showing properties (test specifications) of thetested columns, loading conditions, test results, and SRF reinforcementeffects, on the nine cases under a constant axial force.

FIG. 10 is a graph showing the relationship between horizontal load anddeformation (restoring force characteristic) on the non-reinforced modelcolumn (Case 8). The horizontal axis represents a deformation (δ (mm)),and the vertical axis represents a horizontal load (Q (kN)). In adeformation angle of 0.6% (1/166), a maximum load was increased up to237 kH (Q_(max)), and the non-reinforced model column could not bear theaxial force (η=0.3) in a cycle having a deformation angle of greaterthan 1.5%.

FIG. 11 a graph showing the relationship between horizontal load anddeformation (restoring force characteristic) on the SRF-reinforced modelcolumn (Case 9). The horizontal axis represents a deformation (δ (mm)),and the vertical axis represents a horizontal load (Q (kN)). The modelcolumn was reinforced by bonding a reinforcing member formed of apolyester woven fabric having a thickness (t) of 4 mm, around the modelcolumn. The properties of the reinforcing member are shown in FIG. 43.The bonding strength is about 1 MPa.

In a deformation angle of 0.9%, a maximum load was increased up to 258kH (Q_(max)), and the horizontal load is maintained at a value of 80%(0.8 Q_(max)) or more of a maximum horizontal load until the deformationangle goes beyond 4.0%. Given that 0.8 Q_(max) is a design ultimatestate, an ultimate toughness coefficient (p) is 6.

In the subsequent loading cycles, the peak load is gradually reduced,and minimized (61: minimum point of the peak load) at a deformationangle of 64/400. In the next cycle, the peak load is increased.

FIG. 12 is a graph showing the relationship between the peak value ofthe horizontal load and the deformation in each of the loading cycles,on the nine cases under a constant axial force in FIG. 43. Thehorizontal axis represents a deformation angle (R (%)), and the verticalaxis represents a maximum horizontal load (peak load) in a positivedirection in each of the loading cycles. Numerals in the figure indicatethe case numbers illustrated in FIG. 43.

Referring to FIG. 11, in all of the reinforced cases (Cases 2, 3, 5, 9and 13), a maximum point (maximum value Q_(max)), a minimum point(minimum value Q_(min)) and an apparent gradientchange point (Q_(mid):peak load at the change point) are observed. For example, in Case 9, amaximum point 63, a minimum point 65 and a gradient-change point 67 areobserved. The Case 2 with a small reinforcement amount has a smaller R₄(deformation angle at the minimum point) than that of other cases.

For each of these cases, Q_(mid)/Q_(max) and Q_(min)/Q_(max) werecalculated based on the above maximum point, minimum point andgradient-change point. The result is shown in FIG. 62. Q_(mid)Q_(max)becomes approximately equal to a theoretical value of 0.5 according tothe expression [4]. Q_(min) is reduced from Q_(mid) only by about 10%thereof. This result supports the validity of the aforementionedquantification of the effect of the reinforcing member.

FIG. 13 is a graph showing the relation between structure-membercircumferential-length elongation strain and deformation. The horizontalaxis represents a deformation angle (R (%)), and the vertical axis of astructure-member circumferential-length elongation strain (4) (%)). Themeasurement was performed along five lines provided around thereinforced columns at even intervals. As a result, all of the lines wereuniformly elongated, which supported the validity of the expression[10]. The average values of the test results was plotted to prepare FIG13.

Referring to FIGS. 12 and 13, it is proved that the change of a peakload and the change of a circumferential strain in each of the cycleshave an extremely strong correlation as with FIGS. 5 and 6 which havebeen schematically shown. That is, most of a shear force after themaximum load Q_(max) is borne by the reinforcing member according to themechanism which has been described in conjunction with FIGS. 7 and 8.

In this way, the design calculation can be performed according to theaforementioned quantification models of the reinforcement effect and theperformance of a structure member having a reinforcing member installedthereon.

For the purpose of comparison, the index (reinforcement efficiency) Krepresenting the reinforcement effect, which is defined by the followingexpression [12] according to a method of Japan Society of CivilEngineers, was calculated under the condition of a design ultimate stateof 0.8 Q_(max):S=S _(c) +S _(s) +KS _(s)(A _(f) ,f _(fud))   [12]wherein S is a shear strength after reinforcement, S_(c) being a shearstrength calculated from a concrete strength etc., S_(s) being a shearstrength calculated from a shear reinforcing bar etc., and S_(s) (A_(f),f_(fud)) being a reinforcing-member section A_(f) and areinforcing-member strength f_(fud) which are substituted withcorresponding values in a SRF reinforcing member. FIG. 62 shows thecalculated K (reinforcement efficiency).

Further, a design strength σ_(fd) of the reinforcing member wascalculated back according to a method defined in the design/installationmanual for continuous-fiber reinforcement of Architectural Institute ofJapan. FIG. 43 shows the ratio (reinforcement efficiency:σ_(fd)/σ_(fmax)) of the design strength σ_(fd) to a fracture strengthσ_(fmax) of a SRF reinforcing member. In the above calculation, a shearstrength S after reinforcement was calculated by determining a shearmargin from a roughness coefficient. The calculation was also performedon the assumption that a yield deformation angle was 1/250 in all of thecases.

The reinforcement efficiencies in the both methods (K, σ_(fd)/σ_(fmax))are an approximately the same value of about 0.2 in the case ofF_(c)=3.5 MPa. In the case of F_(c)=18 MPa, it is observed that thevalue tends to be increased. In particular, this tendency is significantin the latter method (σ_(fd)/σ_(fmax)). This would result fromevaluating the reinforcement effect as the square root of areinforcement amount. On the reinforcement efficiency K, there have beenreported experimental values in the range of 0.8 to 1.0 for carbonfibers, and about 0.4 for aramid fibers.

In the above test, a small value or about 0.2 less than that in theaforementioned conventional techniques and 1.0 in a reinforcing bar isobtained. This results from the difference in the material or a lowYoung's modulus of the reinforcing member, and the methodological orstructural difference or a mechanism based on the peeling anddisplacement caused between the reinforcing member and a substrate.

The result obtained by calculating the circumferential strain in thedesign ultimate state (0.8 Q_(max)) from an actually measuredcircumferential length is shown in FIG. 62. An actually measuredultimate circumferential strain (φ₂) is in the range of 0.2 to 0.4%, andthus the damage level of the inside of the structure member isequivalent to that in the conventional techniques such as thereinforcement using carbon fibers.

A reinforcing-member strain (ε_(f)) was calculated from an actuallymeasured shear load (Q) (see the expression [11]), and then a constraintrate (a/L₀) was calculated from the calculated reinforcing-member strain(ε_(f)) and an actually measured circumferential strain (φ)) (see theexpression [6]). This constraint rate (a/L₀) is shown in FIG. 62. Theconstraint rate (a/L₀) is the ratio of a free length (a) to acircumferential length (L₀).

In this test, the tested reinforced column receives a shear force fromone direction. For example, given that when a gap is generated in asurface parallel to a direction of the shear force and thereby a bondingconstraint is completely released and shifted to a geometricalconstraint, two surfaces of the circumference of a square sectionprovide resistance, the constraint rate (a/L₀) is theoretically 0.5.

Referring to FIG. 43, the tested reinforced column has a constraint rate(a/L₀)<0.5 in Cases 3 and 5, and a constraint rate (a/L₀)>0.5 in Cases 9and 13. Thus, it can be said that in the design ultimate state, while abonding constraint in Cases 3 and 5 having a deformation angle R₂ of 1to 2% is still effective, a bonding constraint in Cases 9 and 13 havinga deformation angle R₂ of 4 to 6% is released and completely shifted toa geometrical constraint.

As in the above observation on the test results, the validity of themodel for the effect of a reinforcing member (reinforcement effectmodel) and the model for the performance of a structure member with areinforcing member installed thereon (structure-member performancemodel) has been verified. It is understood that the aforementionednumerical values are experimental values, and a safety factor copingwith variations must be used in actual designs.

A method for determining the material, thickness, installation range andothers (or for designing) of the reinforcing member of the presentinvention will be described below.

FIGS. 39 and 40 are design flowcharts for a reinforcement amount in aprocess of reinforcing a structure member through a method of thepresent invention. With reference to the flowcharts in FIGS. 39 and 40,a method of determining reinforcement parameters will be describedbelow.

As shown in FIG. 39, limit conditions of the weight, shape, function andothers of a structural body are first determined (Step 301).Concurrently, the amplitude, cycle or period, duration and energy of asudden external force likely to act on the structural body aredetermined (Step 302). Among the sudden external force likely to act onthe structural body, a burden share to be borne by a substrate of thestructural body, such as reinforcing bar and concrete, is alsodetermined (Step 303).

Then, in a design process (a) of determining parameters of a structuremember when a structural body or a structure member is newlyconstructed, the parameters of the structure member are determined inconsideration of the data determined in Steps 301 to 303 (Step 304). Theparameters of the structure member may be determined using conventionalstructural design/calculation methods or any other suitablereinforcement manuals.

Then, Among each of a load in ordinary condition, such as the weight ofthe structure member itself, and the sudden external force, a burdenshare to be borne by a method of the present invention is determined(Step 305). Specifically, this step is intended to determine the type,property, and magnitude (amplitude, period, duration, and energy) of thesudden external force to be borne by the method, structure or materialof the present invention. These data may be obtained by subtracting theenergy of a sudden external force bearable with other factors than thereinforcement according to the method of the present invention (theburden share of the substrate etc. determined in Step 303) from thetotal energy of the sudden external force likely to act on thestructural body in the durable term thereof, which has been determinedin Step 301. Thus, if the reinforcement of the present invention is usedin a structural design for a new construction, the materials and/orparameters of a structure member can be determined in an economicallyadvantageous manner by a factor of the reinforcement of the presentinvention.

In a design process (b) involving no determination of any parameter of astructure member, for example, in a design process of reinforcing anexisting structural body or structure member using the reinforcingmember, the data in Step 305 are determined from the data determined inSteps 302 and 303. In this process, such data may be obtained bysubtracting a sudden external force bearable with other factors than thereinforcement according to the method of the present invention from thetotal energy of the sudden external force likely to act on thestructural body in the durable term thereof, as with the process (a).

Then, the amplitude and energy of a sectional force to act on thestructure member are calculated (Step 306). Specifically, based of thetype, property and magnitude of the sudden external force determined inStep 302, the amplitude and magnitude of a sectional force (shear force,axial force, bending moment, etc.) to act on a structure memberincluding a reinforced structure member and other structure members, anda deformation (shear strain, axial strain, bending strain, etc.) of thestructure member. Concurrently, the displacement amplitude andvibrational energy of the entire structure body to be induced by thesudden external force are calculated (Step 307).

The data in Step 306 or 307 may be rigorously calculated by performing astructural analysis calculation, such as a finite element method orframe analysis method taking account of a restoring force characteristicof a reinforced structure member and other structure members as shown inFIG. 51. Alternatively, the data in Step 306 or 307 may be calculated bysimplifying a structural system and setting assumptions such as energyformulas, as in practical structural designs. Except that an associateddeformation range is wider than that in a conventional calculation, thecalculations in Steps 306 or 307 can be performed in the same manner asthat in a structural design for a structure member having a knownrestoring force characteristic.

Then, the relationship of a reinforcement amount, a restoring forcecharacteristic and an axial strain of the reinforced structure member isdetermined (Step 308). The data in Step 308 are determined by thecalculations in Steps 306 and 307. In Step 308, it is generally requiredto perform a feedback from 310 to Steps 306 and 307 through Steps 308,as indicated by the dashed lines of FIG. 59.

Then, limit conditions of the function, usability, recoverability andothers of the structural body after the action of the sudden externalforce such as a seismic force are determined (Step 309), and thedetermined limit conditions are compared with the displacement amplitudeand vibration energy of the structural body calculated in Step 307 todetermine reinforcement parameters (Step 310).

Specifically, the reinforcement parameters are determined by comparingthe deformation of the structural body calculated in Steps 306 to 308with an allowable deformation amount to be derived from the conditionsdetermined in Step 309 or the use conditions of the structural bodyafter the action of the sudden external force such as a seismic force.Step 310 is performed in consideration of the limit conditions of theweight, shape, function and others of the structural body which havebeen determined in Step 301.

If the conditions in Step 309 are determined based on the policy ofsimply preventing collapse against a large earthquake, the allowabledeformation can be set at a large value. If a large deformation involvesthe risk of disaster such as derailment even immediately afteroccurrence of a large earthquake, as in an elevated railroad for thebullet train, the reinforcement amount will be determined inconsideration of such a factor.

Further, if a design ultimate state is defined by a load-withstandingcapacity (strength) corresponding to a given deformation angle of astructure member, the reinforcing member can be designed by thefollowing process.

<1> Among a shear strength Q_(u) expected to a structure member in adesign ultimate state, a shear strength Q_(fu) to be shared by thereinforcing member is determined.

<2> A allowable damage in the structure member is expressed by the totalvalue du of a gap width on the circumference of the structure member,and the value du is converted into a reinforcing-member strain ε_(fu).

<3> A reinforcement amount (thickness t) is calculated from Q_(fu),ε_(fu), a stress distribution in the inside of the structure member anda Young's modulus of the reinforcing member E_(f).

In the above Steps <1> to <3>, the expressions [5] to [11] or modifiedexpressions obtained by modifying the expressions [5] to [11] accordingto the conditions of the structure member. In this case, thereinforcement design has to be performed using a sufficient safetyfactor for a fracture strain because there is a possibility of causing astrain several times larger than the reinforcing-member strain ε_(f) inthe expression [11]. Further, in the calculation of Q_(f), a shear forcetransmitted by a substrate (a shear force transmitted by concrete,reinforcing bar or the like, etc.) may be subtracted, or the subtractionof this shear force may be set at 0 (zero) on the safe side.

A load-withstanding capacity of the structure member after the structuremember goes beyond the above design ultimate state can also becalculated using the expressions [8] and [9]. However, in an actualdesign, the performance of the structure member and the reinforcementamount are experimentally checked as needed as in a conventional designfor reinforced concrete members.

The expressions [5] to [11] are valid even if the substrate is not astructural material such as concrete. Therefore, a structure member canbe produced using a substrate consisting of a material, such as brick orblock, which has been considered as a non-structural material, However,if the rigidity of a substrate is less than that of the reinforcingmember, the deformation of the substrate will be increased beforedevelopment of a reinforcement effect, and a design process including acalculation required for taking account of the increase deformation willbe complicated as compared to the above process. Thus, the material ofthe reinforcing member is selected such that the Young's modulus of thereinforcing member is less than that of the substrate, as describedabove. However, if the Young's modulus of the reinforcing member isexcessive low, the thickness of the reinforcing member required forobtaining a desired reinforcement effect will be increased as shown inthe expressions [3] and [11]. Specifically, the material of thereinforcing member is selected from one having a Young's moduluspreferably in the range of about 1/2 to 1/20, more preferably about 1/5to 1/10, of that of the substrate.

The bonding constraint mechanism becomes effective for a larger gap andcan suppress the deformation (circumferential strain) of the substrateat a smaller value as the reinforcing member has a larger Young'smodulus in the design ultimate state. This deformation (circumferentialstrain) of the substrate is quantified by the expressions [3] and [11].

FIG. 9 is a graph showing a stress-strain relationship of thereinforcing member. The horizontal axis represents a strain (ε) of thereinforcing member, and the vertical axis represents a stress (σ_(f)) ofthe reinforcing member. As described above, the reinforcing member isrequired to have extensibility (large fracture strain). In this regard,the design for the reinforcing member and others is preferably performedin consideration of the curve of the stress-strain relationship as shownin FIG. 9.

Preferably, on the curve of the stress-strain relationship in FIG. 9,the ratio 59 (σ_(fu)/ε_(fu)) of a stress a fu of the reinforcing memberto ε_(fu) of the reinforcing member in a design ultimate state 57 of astructure member is defined as a Young's modulus E_(f) of thereinforcing member in the design ultimate state, and the design of thereinforcing member and others is performed using the Young's modulusE_(f), and a fracture strain ε_(max) and fracture stress (strength)σ_(max) of the reinforcing member The reinforcing member is selected tosatisfy a desired performance of the reinforced structural withreference to the expressions [1] to [9]. When a polyester woven fabricor the like is used as the reinforcing member, it may be heated toprovide a tensile force thereto, and then cooled while maintaining thetensile force or subjected to a treatment for impregnating thereinforcing member with resin (resin impregnation treatment), to provideE_(f) larger than σ_(fu)/ε_(fu). The reinforcing member subjected to theabove treatment can have a higher reinforcement efficient (reinforcementeffect per unit thickness) than that of the reinforcing member withoutthe treatment, to achieve a reduced material cost.

A reinforced structure will be described below in conjunction with anexample where a structure member is a walled column. FIG. 14 is aperspective view of a walled column with the reinforcing memberinstalled thereon. The walled column comprises a column 71 and a wall73. The reinforcing member 75 is installed in such a manner it is woundaround the column 71 and bonded on a reinforcing-member installationrange 79. The reinforcing-member installation range 79 has a larger areathan that of an effective bonding constraint range 77. The effectivebonding constraint range 77 corresponds to a given constraint length(b). The wall 73 is formed with no through-hole for installing thereinforcing member 75.

An epoxy-urethane based one-component adhesive (bonding strength T_(f)=1MPa) is used for the bonding. A polyester sheet member (Young's modulusE_(f)=2100 MPa, thickness t=2 mm) is used as the reinforcing member 75.

Given that a shear force applied in X direction causes a gap in asurface parallel to X direction, a restraint length (b) allowing thebonding constraint to be effectively maintained until the total (d) ofthe gap width measured along a circumferential length parallel to X axisis increased up to 2 mm is calculated as b=1183 mm according to theexpression [3]. Given the a safety factor is 2, a design constraintlength (bd) is about 40 cm.

FIG. 15 is a sectional view of the walled column 69 in FIG. 14. Thedesign constraint length (b_(d)) corresponds to the effective bondingconstraint range 77 in FIGS. 14 and 15.

While a shear bearing force of the walled column 69 is obtained byassigning the dimensions of the column 71, the strength of thereinforcing member 75, the strength of the adhesive and others to theexpressions [4] and [10], it is desired to experimentally check it asneeded because the reinforcement effect and the geometrical restraintlimit are different from those in case where the reinforcing member isfully wound around the column.

A restoring force characteristic in the state after the shear force goesbeyond the design ultimate state to cause fracture of the walled column69 and thereby the bonding restraint is completely released and shiftedto the geometrical restraint can be calculated according to theexpressions [8] an [9].

In this state, at the joint portion between the column 71 and the wall73, the stress af of the reinforcing member 75 is transmitted throughthe inside of the substrate. Thus, the limit ((Q_(max2), R₅): FIG. 5) ofthe validity of the geometrical restraint is determined by smaller oneof the strength of the reinforcing member and the strength of thesubstrate at the joint portion. At any rate, the geometrical restraintcan be maintained up until the limit (Q_(max2), R₅) without forming ahole or the like in the walled column 69 and penetrating the reinforcingmember therethrough.

FIG. 16 is a sectional view of the walled column 69 in FIG. 14. Whilethe reinforcing member 75 installed around the column 71 is opened atthe joint plane between the column 71 and the wall 73, a portion of thecolumn 71 in this open zone 183 is constrained by the wall 73 having thereinforcing member 75 installed thereon. Thus, the entirecircumferential of the column 71 is constrained by the reinforcingmember 75 and the wall 73 having the reinforcing member 75 installedthereon. In this case, the geometrical constraint is achieved in aneffective geometrical constraint range 81.

Alternatively, a given reinforcement effect can be obtained byinstalling the reinforcing member on only one of the surfaces of astructure member such as wall. Further, a earthquake-resisting wall maybe formed by placing a pair of boards, such as precast concrete boards,in parallel with one another between two existing columns to form awall, pouring concrete or filling sands or the like into the spacebetween the boards, and installing the reinforcing member around thewall and/or the columns.

Thus, according to the above reinforced structure, the reinforcingmember having a given rigidity and extensibility is installed a portionof the surface of a structure member to be reinforced, to reinforce thestructure member. Thus, the reinforcement can be applied to a structuremember having any shape such as a convexo-concave or irregular shape. Inaddition, the reinforcing member can be installed without forming anyhole or the like in a structure member subject to reinforcement.Therefore, a reinforced structure excellent in toughness andload-withstanding capacity can be constructed quickly and readily at alow cost.

Further, the reinforcement effect of the reinforcing member and theperformance of the reinforced structure with the reinforcing member canbe quantified and/or evaluated according to the aforementionedreinforcement effect model and structure-member performance model. Thus,the reinforcing member can be adequately selected and designed dependingon a structure member subject to reinforcement.

As seen in the reinforcement effect model and the structure-memberperformance model, the reinforcing member and the adhesive according tothe first mode of embodiment can be effectively selected depending thematerial, category and type (existing or new construction, etc.) of astructure member. Thus, the labor load and cost for constructing thereinforced structure having a desired performance andpreparing/installing the reinforcing member having a desired reinforcingeffect or quake-resistance effect can be constructed can be reducedwhile shortening a construction period.

As a substitute for the reinforcing member 75, a strip-shaped polyesterbelt 199 as shown in FIG. 21 may be used. The material of the polyesterbelt 199 may be polyester-based fibers for use in bell rope or the like.While a reinforcing sheet such as a construction sheet has a strength inthe range of 500 to 1000 kgf/3 cm width, the polyester belt 199 has astrength of about 15000 kgf/5 cm width.

Another reinforced structure will be described below in conjunction withan example where a structure member has an H shape. FIG. 17 is aperspective view of an H-shaped structure member 143 afterreinforcement. As shown in FIG. 17, the H-shaped structure member 143 isreinforced using a reinforcing member 145 and a granular filler material147.

The sheet-shaped reinforcing member 145 is shaped into a cylindricalshape and disposed around the H-shaped structure member 143 to form aspace therebetween. The granular filler material 147 is filled in thespace between the H-shaped structure member 143 and the reinforcingmember 145. For example, a fiber or rubber-based sheet material may beused for the reinforcing member 145. For example, the filler material147 may be a natural granular material, such as sands, or an artificialgranular material, such as resin.

The glandular filler material 147 transmits a stress to the reinforcingmember 145 while being deformed in connection with energy loss. Thus,differently from the conventional reinforcing techniques such ascontinuous fibers or steel-plate wrapping, there is no need for fixingthe filler material with resin or adhesive. Even if the filler materialis bonded or fixed for the reason of construction, the bonding orfixation may be performed in a temporary level allowing the shape of thefiller material to be held under ordinary loading or in earth tremor.

This type of reinforced structure may be used to reinforce a structuremember having a complicated sectional shape, as well as the H-shapedstructure member 143. In this type of reinforced structure, when thestructure member is deformed in connection with an apparent volumeexpansion, the granular filler material 147 transmits the apparentvolume expansion to the reinforcing member to provide enhancedreinforcement effect. Further, the granular filler material may beformed of an inorganic noncombustible material having high heat capacityto have an additional effect of protecting the H-shaped structure member143 from heat.

Still another reinforced structure will be described below inconjunction with an example where a structure member is hollow. FIG. 18is a perspective view of a hollow structure member 149 afterreinforcement. As shown in FIG. 18, the hollow structure member 149 isreinforced using a reinforcing member 145 and a granular filler material147.

The sheet-shaped reinforcing member 145 is installed on and around theouter surface of the cylindrical hollow structure member 148. The insideof the hollow structure member 149 is filled with the granular fillermaterial 145. For example, a fiber or rubber-based sheet material may beused for the reinforcing member 145. For example, the filler material147 may be a natural granular material, such as sands, or an artificialgranular material, such as resin.

The granular filling material 147 is installed to fill the space of thehollow structure member 149. In addition, the glandular filler material147 transmits a stress to the reinforcing member 145 while beingdeformed in connection with energy loss. Thus, there is no need forsolidifying the filler material filled in the inside of the structuremember as in concrete used in a concrete-filling steel-pipe constructionmethod.

In this reinforced structure, when a hollow structure member isreinforced, the granular filler material 147 is installed inside thestructure member to provide enhanced reinforcement effect. The fillermaterial acts to transmit to the reinforcing member 145 an apparentvolume expansion cased when the hollow structure member 149 is fracturedin connection with energy loss. While the hollow structure member in theabove example has a circular sectional shape, the present invention isnot limited to such a shape.

In addition, in order to reinforce the H-shaped structure member 143 orthe hollow structure member 149 used the glandular filler material 147,compounding this reinforced structure and other reinforced structure canbe applied.

Next, an example of the reinforced structure in case of using pluralityof reinforcements will be described. FIG. 19 is a partial sectional viewof a reinforced member 181. In FIG. 19, the member 181 is reinforced byuse of a protective reinforcement 183, a reinforcement 185, areinforcement 187, and a protective reinforcement 189.

The protective reinforcement 183, the reinforcement 185, thereinforcement 187, and the protective reinforcement 189 aresequentially, from inside to outside, disposed on the member 181. Theprotective reinforcement 183 is disposed in order to protect thereinforcements 185 and 187 and the protective reinforcement 189 from theaction of the member 181. For example, when the member 181 is made of amaterial, such as concrete, from which alkali separate outs, and thereinforcements 185 and 187 and the protective reinforcement 189 are madeof a material, such as polyester fiber, of low alkali resistance, theprotective reinforcement 183 is made of a material, such as a resin,which has a function to prevent separation of alkali from the member181.

The protective reinforcement 189 is disposed in order to prevent adeterioration in the function of the protective reinforcement 183 andthe reinforcements 185 and 187 which would otherwise result from theaction of substances in the external environment. For example, when theprotective reinforcement 183 and the reinforcements 185 and 187 arepolyester-fiber sheets or the like, these reinforcements are likely tobe deteriorated by ultraviolet rays. Thus, the protective reinforcement189 is made of epoxy, urethane, or a like resin to thereby prevent adeterioration of the reinforcements disposed inside the same. Afireproof belt can also be used as the protective reinforcement 189.

The reinforcement 185 and the reinforcement 187 differ in areinforcement effect on the member 181. For example, the reinforcement187 is made of polyester fiber or the like, and the reinforcement 185 ismade of a resin or fiber impregnated with resin. In this case, thereinforcement 187 exhibits a reinforcement effect at up to a largestrain (up to about 15%) of the member 181, whereas the reinforcement185 exhibits a reinforcement effect at a low strain (not greater than1%) of the member 181.

When the member 181 is to be reinforced merely by use of a polyesterfiber reinforcement, the reinforcement must assume a large thickness inorder to exhibit a reinforcement effect at the stage of a small strainof the member 181, since the reinforcement is smaller in Young's modulusthan the member 181. However, through combined use of the polyesterfiber reinforcement and a reinforcement made of a material, such as aresin or fiber impregnated with resin, having a large Young's modulus,the polyester fiber reinforcement thinner than that used solely forreinforcing the member 181 can exhibit a reinforcement effect even at asmall strain (not greater than 1%) of the member 181. Also, being bondeddirectly to the surface of the member 181 or protective reinforcement183, the reinforcement 185 can exhibit a reinforcement effect at smallstrain. The protective reinforcement 183 assumes, as needed, a functionfor transmitting a shear force induced between the surface of the member181 and the reinforcement 185. For example, a resin primer is used asthe protective reinforcement 183.

The reinforcement 185 and the reinforcement 187 may differ in amechanism for yielding a reinforcement effect so as to exhibit areinforcement effect under different load conditions and over the rangeof deformation. For example, there are combined a method in which partof a shear force imposed on the member 181 is directly borne by areinforcement, and a method in which the expansion of an apparent volumeof the member 181 is restrained.

Material and configuration of the reinforcement 187 can be such that areinforcement effect is yielded through restraint of the expansion of anapparent volume. With the aim of enhancing the load bearing capacity ofthe member 181 through enhancement of shear fracture yield strength ofthe member 181, the reinforcement 185 is made of an iron plate, carbonfiber, aramid fiber or the like. Through direct transmission of a shearforce between the member 181 and the reinforcement 185, the shear forceis shared between the member 181 and the reinforcement 185, whereby themember 181 is reinforced. Also, a polyester sheet or belt or the likewhose rigidity is enhanced through impregnation with resin or throughapplication of adhesive to the entire surface thereof can be used as thereinforcement 185. This yields a merit in that the reinforcement 185 andthe reinforcement 187 can be continuously laid.

FIG. 20 is a graph showing the relationship between load and deformationwith respect to the member 181 which is reinforced by means of amultilayer configuration as shown in FIG. 19. In FIG. 20, the verticalaxis represents load, and the horizontal axis represents deformation.The load represents section forces of the member 181, such as axialforce, bending moment, shear force, etc. The deformation representsdeformations corresponding to the section forces; specifically, axialcontraction, flexural modulus, shearing strain, etc. A curve 193 whichrepresents the case of reinforcement by means of multilayerconfiguration indicates that the member 181 has load bearing capacityover a wider range of deformation as compared to the case of noreinforcement employed as represented by a curve 191.

FIG. 20 shows an ordinary example in which the effective deformationrange of the reinforcement 185 does not overlap with that of thereinforcement 187; i.e., a slight reduction in load bearing capacityoccurs between an effective range 195 of the reinforcement 185 and aneffective range 197 of the reinforcement 187. The reduction of loadbearing capacity can be avoided by overlapping the effective deformationranges of the reinforcements 185 and 187.

According to this reinforced structure, reinforcements of differentcharacteristics are disposed in layers on the exterior of a member, tothereby exhibit a reinforcement effect over a wide range of loadconditions of the member as well as over a wide range of conditions ofthe external environment. The member 181 is not limited to a concretemember or the like but may be the filler 147 shown in FIGS. 17 and 18.In this case, through employment of the filler 147 that yields an effectequivalent to that yielded by the protective reinforcement 183, theprotective reinforcement 183 may be omitted.

Notably, a beltlike reinforcement of high strength and rigidity, such asthe polyester belt 199, can be used as the reinforcement 185 to bebonded directly to the surface of the member 181 or protectivereinforcement 183. Since the polyester belt 199 can be woven intotexture that exhibits greater Young's modulus per unit width as comparedwith a polyester sheet, the polyester belt 199 can be used as thereinforcement 185, which exhibits a reinforcement effect at the stage ofsmall strain. For example, according to the tensile test result of thepolyester belt 199 having a width of 64 mm and a thickness of 4 mm,strain is 2% under a load of 2500 kgf.

When the polyester belt 199 is used as the reinforcement 185, a column205 shown in FIGS. 22 to 25 corresponds to the member 181 of FIG. 19. Areinforcement method by use of the polyester belt 199 as shown in FIGS.22 to 25 will be described in the subsequent section of an eighthembodiment.

FIG. 21 is a plan view of the polyester belt 199; FIGS. 22 and 23 areperspective views showing examples of the column 205 reinforced by useof a beltlike reinforcement 201; and FIG. 24 is an elevation of thecolumn 205 shown in FIG. 23.

First, reinforcement shown in FIG. 22 will be described. In FIG. 22, aplurality of beltlike reinforcements 201 are disposed at predeterminedintervals on the column 205 in such a manner as to be wound about thecolumn 205. End portions of each of the beltlike reinforcements 201,which are wound about the column 205, can be connected together by meansof bonding and/or a clasp, which are mechanical joints. Use ofmechanical joints can implement reinforcement in a short period of timeand is thus suited for urgent reinforcement to be performed immediatelyafter an earthquake disaster. Beltlike reinforcements 203 bonded axiallyto the column 205 can be expected to yield the effect of controlling acrack(s) extending along a direction intersecting the same.

Next, reinforcement shown in FIGS. 23 and 24 will be described. Thebeltlike reinforcement 201 is compactly wound about the column 205 shownin FIGS. 23 and 24. While tension is imposed on the beltlikereinforcement 201 in the direction of arrow C, the beitlikereinforcement 201 is wound onto the column 205 in the direction of arrowD, thereby enhancing a reinforcement effect. The beltlike reinforcement201 is bonded directly to the column 205. Comer portions of the column205 are not particularly required to be chamfered or to undergo likeprocessing in order to avoid breaking textile at the corner portions.However, a beltlike reinforcement (not shown) bonded to a corner portionof a member in parallel with the edge of the corner portion can beexpected to yield the effect of easing stress concentration of an edgeportion on a reinforcement.

As shown in FIG. 24, the beltlike reinforcement 201 is wound onto anupper end portion 207 and lower end portion 211 of the column 205 inparallel with the circumferential direction of the column 205 and isspirally wound onto a general portion 209 such that, as the beltlikereinforcement 201 is wound one turn, it axially advances by the widththereof, whereby the beltlike reinforcement 201 can be wound about thecolumn 205 compactly and evenly. Also, the winding direction (clockwiseor counterclockwise) can be altered so as to wind the beltlikereinforcement 201 onto the column 205 in two layers, three layers, etc.,thereby enhancing a reinforcement effect. In this case, after winding ofthe first layer is completed, an adhesive is applied to the first layer,and then the second layer is formed through winding such that thewinding pitch is shifted by half the width of the beltlike reinforcement201 between the first and second layers, thereby preventing thepotential move of the beltlike reinforcement 201.

In order to allow the reinforcing member to be in close contact with thesubstrate in the above winging manner, it is required that thereinforcing member can be bent at an angle equal to or greater than thecorner angle of the column, and sheared at an angle equal to or greaterthan the displacement angle between the parallel winding and the spiralwinding. In a typical column, the bending angle and the displacementangle are 90 degree or less and 2-degree or less, respectively. When areinforcing member is installed in a crossed manner as described laterin connection with FIG. 56, it is preferable that the reinforcing membercan be sheared at a large angle.

FIG. 25 is a sectional view of a surface portion of the column 205 shownin FIGS. 22 to 24. As shown in FIG. 25, the beltlike reinforcement 201is bonded directly to the column 205 by use of an adhesive 213.

The beltlike reinforcement 201 shown in FIGS. 22 to 25 is, for example,the polyester belt 199 shown in FIG. 21. As mentioned in the sections ofthe second and seventh embodiments, the polyester belt 199 is made ofpolyester fiber, which is a material for a strap or the like. Thepolyester belt 199 is used particularly in view of the following: beinghigher in rigidity and strength than a civil engineering sheet, thepolyester belt 199 restrains an increase in the width of crack in thecolumn 205 and controls the deformation of an apparent volume for therange of small strain.

Next will be described the method for calculating the amount ofreinforcement in the case of reinforcement for restraining the width ofcrack for the range of small strain of the column 205. FIG. 26 is a viewshowing an effective bond length between the beltlike reinforcement 201and a crack 215.

When a member is locally ruptured due to bending, axial force, shearforce, or a like force imposed thereon, the crack 215 appears on thesurface of the member. In FIG 126, the crack 215 is made on the surfaceof the column 205, to which the beltlike reinforcement 201 is bondeddirectly. The belt width 219 of the beltlike reinforcement 201 is w. Aforce which attempts to expand the crack 215; i.e., tension 221, isimposed on the beltlike reinforcement 201 in the amount of q per belt.In FIG 145, the beltlike reinforcement 201 restrains crack width 217 tod or less.

Stress concentration is present in the vicinity of the crack 215. Width223 (a) extending in opposite directions from the crack 215 is thelength of a region where a bonding effect is lost due to shear fractureof the adhesive 213 or member surface. Width 223 (a) is hereinaftercalled a free length. Restraint length 225 (b) is a natural restraintlength of the column 205 and is measured from a free end. Accordingly,the beltlike reinforcement 201 is bonded to the column 205 alongfixation length s=b−a.

Restraint length 225 is the length of a single side in the case arectangular cross section, as in the column 205, and is the length of anarc corresponding to a central angle of about 90 degrees in the case ofa circular cross section. When these lengths are significantly large ascompared with belt width 219 (w) of the beltlike reinforcement 201,restraint length 225 is a length along which an effective bonding forceis not zero.

When the crack 215 is located at around the center of a certain surfaceof a member having a rectangular cross section, restraint length 225extends to another surface of the member.

When k represents the rigidity of the beltlike reinforcement 201, freelength a; i.e., width 223, crack width 217 (d), and tension 221 (q) arerelated as expressed byq=kd/a   21)when τ represents the average shear force between the beltlikereinforcement 201 and the column 205 as measured within fixation lengths=b−a, τ is expressed byτ=q/(w·s)   22)

When free length a is eliminated from Eq. 21) and Eq. 22), tension 221(q), average shear force T, and crack width 217 (d) hold quadraticrelation as represented byq=1/2[τwb±{(τwb)²−4τwkd} ^(0.5)]  23)

This relation has two solutions q at maximum crack width d_(max) orless. Since a larger solution is first realized, the larger solution isemployed. Then, q falls somewhere between maximum value q_(max) andminimum value q_(min) according to crack width 217 (d).q_(max)=τwb   24)q_(min)=0.5τwb   25)

Crack width d_(max) corresponding to minimum value q_(min) is expressedbyd _(max) =τwb ²/(4k)   26)

When the crack width is in excess of d_(max), Eq. 23) does not have asolution. That is, such a mechanism does not hold true. Maximum valueq_(max) and minimum value q_(min) when the beltlike reinforcement 201bears part of a force attempting to expand the crack 215 are obtainedfrom the above relations, thereby enabling design of structuralreinforcement through utilization of the above-mentioned mechanism.Values obtained from Eq. 24) to Eq. 26) are proportional to bondingforce T (average shear force) between a member, such as the column 205,and the beltlike reinforcement 201.

When a material which is inexpensive and has excellent stretchability,such as the polyester belt 199, is used as the beltlike reinforcement201, since the Young's modulus of the material is about one-tenth thatof concrete or one-hundredth that of iron, the following problem isinvolved. Even when the adhesive 213 having large average shear force τis used for bonding, the material encounters difficulty in sharing witha member a force which is elastically imposed on the member, withoutformation of the crack 215. However, when a reinforcement effect isparticularly needed at the stage of small deformation, a polyester beltor the like is impregnated with resin to thereby enhance the rigidity ofthe reinforcement. The thus-prepared reinforcement is used together withan epoxy resin adhesive.

The polyester belt 199 has a woven body of a weft double weave using apolyester-fiber yam with 1700 dtex (dcitex). The polyester belt 199 hasa Young's modulus of 4676 MPa, a thickness of 4 mm, a fracture strain of15%, and a specific gravity of 0.98. Since the polyester base yam has aspecific gravity of 1.4, a void ratio of the polyester belt 199 is(1.4/0.98=) 1.43 when expressed by the ratio of specific gravity.

The column 205 is made of reinforced concrete. Concrete has acompression fracture strength of 13.8 MPa (135 kgf/cm²), a Young's modusof 19500 MPa, and a direct shear strength of about 2.6 MPa. Thereinforcing member was installed without performing any chamfering andany adjustment of surface unevenness.

Rubiron 101 (one-component: available from Toyo Polymer Co.) was used asan adhesive. The layer of the adhesive is 1 mm. The adhesive has abonding strength of about 1 MPa (10 kgf/cm²), and a specific gravity of1.4. A part of the adhesive is infiltrated into the texture of thepolyester belt 199, and cured. However, even if the entire adhesive of 1mm thickness enters into the void of the polyester belt 199, it willoccupy only about 70% of the void of the polyester belt 199, and thebreathability or air-permeability of the reinforcing member can bemaintained. While Rubiron 101 is not a non-solvent adhesive, it has beenexperimentally verified that the same reinforcement effect can beobtained even using a non-solvent adhesive having a bonding strengthequivalent to that of Rubiron 101.

With respect to the effect of the reinforcement using the impregnatedaramid fibers as disclosed in the aforementioned Japanese PatentLaid-Open Publication No. 8-260715, a test result of the same method asthat in FIG. 29 is introduced in a number of publications. However, noneof these publications reports the increase of load after Q min, asindicated by the load-deformation curve 243 b in FIGS. 30 and 50, andthe test ends up with the fracture of the aramid-fiber reinforcingmember before Q min or the peeling of the reinforcing member from astructure member.

A case study is conducted for the structure of FIG. 25 under, forexample, the following conditions: the beltlike reinforcement 201 is thepolyester belt 199 having a width of 64 mm and a thickness of 4 mm; thecolumn 205 is a reinforced-concrete column having a restraint length 225of b=30 cm; and the adhesive 213 is LUBIRON, which is the trade name ofan epoxy urethane adhesive produced by Toyo Polymer Corp. In this study,calculation conditions are as follows: average shear force T=10 kgf/cm²;the beltlike reinforcement 201 (polyester belt 199) has a belt width 219of w=6.4 cm and a restraint length 225 of b=30 cm; and the beltlikereinforcement 201 (polyester belt 199) has a rigidity of k=153000kgf/cm².

Calculation of maximum value q_(max), minimum value q_(max), and maximumcrack width d_(max) by use of Eq. 4) to Eq. 6) gives the followingresults: maximum value q_(max)=1920 kgf; minimum value q_(min)=960 kgf;and maximum crack width d_(max)=0.12 cm.

Accordingly, when this reinforcement is carried out, cracking can berestrained up to maximum crack width d_(max)=1.2 mm. A single beltlikereinforcement 201 (polyester belt 199) bears a tension 221 of q=0.9 tf.

FIG. 27 is a schematic view of the column 205 subjected to an axialforce, bending, and a shear force. FIG. 28 is a view showing a forcewhich attempts to expand the crack 215 formed in the column 205.Described below is a reinforcement effect to be yielded in the casewhere the column 205 is reinforced by use of the polyester belt 199,which serves as the beltlike reinforcement 201, according to the methodof FIG. 24; and the thus-reinforced column 205 is loaded in thefollowing manner: while axial force 229 (P) is applied to the column205, a horizontal force is applied to the column 205 so as to repeatedlygenerate bending moment 231 (M) and shear force Q.

The column 205 is assumed to be an ordinary structural column.Conditions of study are as follows: shear force 227 (Q) is horizontallyimposed on the column 205 at the middle of height h; i.e., at height(h/2); and the upper and lower ends of the column 205 slide horizontallywithout involvement of rotation. As a result, a horizontally even shearforce (resultant force Q) and an axial force (resultant force P) aregenerated in the column 205. A bending moment is M=Qh/2 at the upper endof the column 205, zero at the middle, and −M at the lower end.

When shear force 227 (Q) reaches maximum shear force Q_(max), whichdepends on the conditions of reinforcing bars and concrete of the column205, the crack 215 is generated in a direction of angle θ 237. A forcewhich attempts to horizontally expand the crack 215 is shear force 227(Q) imposed on the column 205. The force is considered to be borne bythe beltlike reinforcement 201 which is present over the rangerepresented by arrow c 233. Since a single belt of the beltlikereinforcement 201 has a width of w and exhibits a tension of q, aresultant force Q of the beltlike reinforcement 201 present over therange represented by arrow c 233 is represented by Q=q·2C/w.

Since the column 205 has a rectangular cross section, the beltlikereinforcement 201 on the near-side surface thereof and that on thefar-side surface thereof are involved in reinforcement; therefore, acoefficient of 2 is used. As seen from FIG. 28, length C of arrow c 233is represented by C=b tan τ. Generally, shear force Q is partially borneby a member. However, it is assumed that, when the deformation of themember exceeds a level corresponding to around Q_(max), at which a beltbecomes significantly effective, substantially the entire shear force isborne by belt tension.

When angle θ 237 is 45 degrees, width 235 of the column 205 is b(restraint length)=30 cm. Accordingly, horizontal forces Q_(max) andQ_(min) corresponding to maximum value q_(max), and minimum value qminwhich are previously calculated for the polyester belt 199 (width 64 mmand thickness 4 mm) by use of Eq. 24) to Eq. 26) are obtained asQ_(max)=q_(min)2b/w=18000 kgf and Q_(min)=q_(min)2b/w=9000 kgf. Thus, byvirtue of the effect of the reinforcement, a horizontal resistance forceof not less than 9 tf can be maintained when the width of the crack 215is not in excess of d_(max)=1.2 mm.

Next will be described the results of a test conducted in the followingmanner: a horizontal force was repeatedly applied to an unreinforcedcolumn 205 and to a column 205 reinforced by use of the polyester belt199 (width 64 mm and thickness 4 mm), which serves as the beltlikereinforcement 201 shown in FIG. 24, under the conditions of FIG. 27while displacement was controlled. Other test conditions were asfollows: the concrete strength of the column 205 is 135 kgf/cm²; theaxial ratio of reinforcement is 0.56%; the ratio of shear reinforcingbar is 0.08%; an axial force is held constant at 37 tf (axial forceratio 0.3).

FIG. 29 is a schematic view showing the deformation of the column 205.FIGS. 30 to 35 show experiment results, in which horizontal displacementδ_(h) 239 represents the horizontal displacement of the column 205; andvertical displacement δ_(v) 241 represents the vertical displacement ofthe column 205. FIG. 30 is a graph showing the relationship betweenhorizontal force Q of the column 205 and an envelope indicative ofdisplacement hysteresis of the column 205. FIG. 31 is a graph showingthe relationship among the horizontal displacement of the column 205,the vertical displacement of the column 205, and a horizontal force.FIG. 32 is a graph showing restoring-force characteristics of the column205.

In FIG. 30, the horizontal axis represents horizontal displacement δ_(h)(239) of the column 205, and the vertical axis represents horizontalforce Q (shear force 227). In FIG. 32, the horizontal axes representhorizontal displacement δ_(h) (239) of the column 205 and the angle ofdeformation, and the vertical axis represents horizontal force Q (shearforce 227).

In FIG. 30, a reinforcement-absent curve 243 a is an envelope asobserved when the column 205 is not reinforced with the beltlikereinforcement 201, and a reinforcement-present curve 243 b is anenvelope as observed when the column 205 is reinforced. Thereinforcement-present curve 243 b is an envelope along the followingpoints on a hysteretic loop 253 shown in FIG. 32: a point correspondingto a level 255 a equivalent to the level of the Great Hanshin EarthquakeDisaster, a point corresponding to a level 255 b equivalent to two timesthe level of the Great Hanshin Earthquake Disaster, a pointcorresponding to a level 255 c equivalent to three times the level ofthe Great Hanshin Earthquake Disaster, a point corresponding to a level255 d equivalent to five times the level of the Great Hanshin EarthquakeDisaster, etc.

In FIG. 31, the horizontal axis represents horizontal displacement δ_(h)(239); the upward vertical axis represents horizontal force Q (shearforce 227); and the downward vertical axis represents verticaldisplacement δ_(v) (241). A reinforcement-absent curve 243 a and areinforcement-present curve 243 b are envelopes similar to those shownin FIG. 30. The reinforcement-absent curve 245 a shows verticaldisplacement 6 of the column 205 which is not reinforced with a beltlikereinforcement. The reinforcement-present curve 245 b shows verticaldisplacement δ_(v) of the column 205 which is reinforced with thebeltlike reinforcement 201 (polyester belt 199).

As shown in FIGS. 30 and 31, when Q_(max1) represents the maximumhorizontal force in the case of no reinforcement being employed asrepresented by the reinforcement-absent curve 243 a; Q_(max2) representsthe maximum horizontal force in the case of reinforcement being employedas represented by the reinforcement-present curve 243 b; and Q_(min)represents the minimum horizontal force in the case of reinforcementbeing employed as represented by the reinforcement-present curve 243 b,experiment data show Q_(max1)=17.5 tf, Q_(max2)=18 tf, and Q_(min)=7 tf.

In FIG. 31, the reinforcement-absent curve 243 a, which shows horizontalforce Q of the unreinforced column 205, and the reinforcement-absentcurve 245 a, which shows vertical displacement δ_(v) drop sharply at andafter the time when horizontal force Q becomes Q_(max1). This supportsthe aforementioned assumption that, in the case of the reinforced column205, the beltlike reinforcement 201 (polyester belt 199) exhibits areinforcement effect; i.e., the beltlike reinforcement 201 bearssubstantially the entire shear force in a horizontal-displacement regionranging from a horizontal displacement corresponding to Q_(max2) to ahorizontal displacement corresponding to Q_(min).

The experimentally obtained value of minimum horizontal force Q_(min)appearing on the reinforcement-present curve 243 b is lower than acalculated value of 9 tf, which is obtained through calculation usingthe models of FIGS. 27 and 28. This can be said to be an experimentalerror and implies the occurrence of a drop in strength at the bond areabetween the concrete surface of the column 205 and the beltlikereinforcement 201 (polyester belt 199). The value of maximum shear forceQ_(max2) is substantially equal to a calculated value of 18 tf.

As shown in FIG. 29, when horizontal displacement δ_(h) of the column205 is displacement amplitude δ_(hc) 247, the reinforcement-presentcurve 243 b indicative of horizontal force Q has a horizontal-forceinflection point 249, and the reinforcement-present curve 245 bindicative of vertical displacement δ_(v) has a vertical-displacementinflection point 251. Displacement amplitude δ_(hc) 247 is horizontaldisplacement δ_(h) at around a point corresponding to the level 255 cequivalent to three times the level of the Hyogo-Ken Nanbu Earthquake onthe hysteretic loop 253 shown in FIG. 32; i.e., about 140 mm (angle ofdeformation 0.15 rad).

FIG. 33 is a graph showing the relationship between cumulativehorizontal displacement Σε_(h) and hysteretic absorbed energy W in thecolumn 205. FIG. 34 is a detailed view of FIG. 33. In FIG. 33, thehorizontal axis represents cumulative horizontal displacement Σε_(h),and the vertical axis represents hysteretic absorbed energy W.

Cumulative horizontal displacement Σε_(h), which is represented by thehorizontal axis in FIGS. 33 and 34, was calculated by the equation shownbelow. In the equation, i is the number of steps in data recording, andn is the current number of steps. Cumulative horizontal displacementΣε_(h) is calculated as an indicator of a position on the hystereticloop 253 shown in FIG. 51. $\begin{matrix}{{\sum\limits^{\quad}\quad\delta_{h}} = {\sum\limits_{i = 1}^{n}\quad{{\delta_{{hi} + 1} - \delta_{hi}}}}} & \left. 27 \right)\end{matrix}$

Cumulative absorbed energy W represented by the vertical axis wascalculated by the following equation. Cumulative absorbed energy W iswork done by horizontal force Q; i.e., by shear force 227.W=∫Qdδ_(h)   28)

When a certain column 205 of a structure bears an axial force 229 of P,corresponding mass m can be represented by use of gravitationalacceleration g as m=P/g. Thus, of energy which is input to the structureand consumed until completion of vibration, work E which is done byshear force 227 imposed on the column 205 is approximated by thefollowing expression by use of velocity response spectrum δ_(v) ofearthquake motion.E=0.5(P/g)Sv ²   29)

The curve of hysteretic absorbed energy 257 shown in FIG. 33 showshysteretic absorbed energy which is calculated from the experimentallyobtained hysteretic loop 253 shown in FIG. 51, by use of Eq. 28). Thestraight lines indicative of a level 259 a equivalent to the level ofthe Great Hanshin Earthquake Disaster and a level 259 b equivalent tofive times the level of the Great Hanshin Earthquake Disaster representvalues which are calculated by Eq. 29) for comparison with the curve ofhysteretic absorbed energy 257. FIG. 53 additionally show values whichare calculated by Eq. 29) and represented by the straight linesindicative of a level 259 c equivalent to two times the level of theGreat Hanshin Earthquake Disaster and a level 259 d equivalent to threetimes the level of the Great Hanshin Earthquake Disaster. Velocityresponse spectrum used in the calculation by Eq. 29) was Sv=90 cm/s at anatural period of 0.3 sec appearing in the record of Kobe MarineMeteorological Observatory.

FIG. 35 is a graph showing the relationship between calculatedcumulative horizontal displacement Σε_(h) and vertical displacementδ_(v) by use of Eq. 27). In FIG. 35, the horizontal axis representscumulative horizontal displacement Σδ_(h), and the vertical axisrepresents vertical displacement δ_(v) (241). As mentioned previously inthe description which was given with reference to FIG. 31, whenhorizontal displacement is horizontal amplitude δ_(hc) 247; i.e., about140 mm, the vertical-displacement inflection point 251 appears. At thistime, cumulative horizontal displacement Σδ_(h) is about 1500 mm. Asshown in FIG. 35, vertical displacement δ_(v) is not greater than 5 mm(strain 0.5%) until cumulative displacement reaches about 1500 mm at thevertical-displacement inflection point 251.

The above-described experiment demonstrated the following:

-   -   {circle over (1)} A reinforcement effect was exhibited for        low-strength concrete (135 kgf/cm²), which encounters difficulty        in being reinforced by a conventional method.    -   {circle over (2)} A reinforcement effect was exhibited        continuously over a range from small strain to large        deformation.    -   {circle over (3)} It was confirmed that the        reinforcement-present curve 243 b shown in FIG. 49 has two        inflection points of horizontal force (a point of Q=Q_(max2) and        a point of Q=Q_(min); i.e., the horizontal-force inflection        point 249).    -   {circle over (4)} It was confirmed that the        reinforcement-present curve 245 b shown in FIG. 31 has a single        inflection point of vertical displacement δ_(v) (the        vertical-displacement inflection point 251). This inflection        point corresponds to the horizontal-force inflection point 249        (Q=Q_(min)) mentioned above in {circle over (3)}. The        vertical-displacement inflection point 251 is a point at which a        mechanism represented by Eq. 21) to Eq. 26) shifts to a        mechanism in that the cross-sectional shape of the column 205        begins to be deformed, and great axial deformation arises, since        the mechanism represented by the equations is disabled as a        result of a series of events of cumulative damage to concrete        due to repeated load; a drop in concrete strength; a drop in        bonding strength τ between the beltlike reinforcement 201        (polyester belt 199) and the concrete surface of the column 205;        and an increase in crack width 217 beyond limit d_(max).    -   {circle over (5)} Vertical displacement δ_(v) (axial contraction        of the column 205) is not greater than 0.5% until the second        inflection point of horizontal force Q; i.e., the horizontal        inflection point 249 at which Q becomes Q_(min), is reached;        i.e., until vertical displacement δ_(v) reaches        vertical-displacement inflection point 251. This range of        vertical displacement δ_(v) is tolerable such that a structure        can be practically reused after an earthquake.    -   {circle over (6)} Conceivably, in the case of reinforcement        being not carried out (as represented by the        reinforcement-absent curves 243 a and 245 a in FIGS. 30 and 31),        before hysteretic absorbed energy reaches the Great Hanshin        Earthquake Disaster equivalent thereof, vertical displacement        δ_(v) increases abruptly with a resultant collapse of the        structure.    -   {circle over (7)} In the case of reinforcement being carried        out, vertical displacement δ_(v) is not greater than 0.5% until        hysteretic absorbed energy 257 shown in FIGS. 33 and 34 becomes        about 2.5 times the hysteretic absorbed energy of the Great        Hanshin Earthquake Disaster. This range of vertical displacement        δ_(v) is tolerable such that a structure can be practically        reused after an earthquake.    -   {circle over (8)} In the case of reinforcement being carried        out, as shown in FIG. 35, when hysteretic absorbed energy        becomes greater than about 2.5 times that of the Great Hanshin        Earthquake Disaster (when cumulative horizontal displacement        Σδ_(h) becomes greater than about 1500 mm), vertical        displacement δ_(v) increases gradually. However, as shown in        FIGS. 50 and 32, horizontal yield strength increases, and        absorbed energy per cycle increases, whereby a vibration-damping        effect is enhanced, thereby yielding a great collapse prevention        effect.

As seen from the results of experiment shown in FIGS. 30 to 35, in whichthe beltlike reinforcement 201, such as the polyester belt 199, isbonded directly to a member, such as the column 205, exhibitscontinuously a reinforcement effect on deformation ranging from a smallone as observed after formation of the crack 215 to a large one.

A conventional reinforcement method in which a member is wrapped withreinforcement is characterized in that, in order to prevent formation ofcracks, a reinforcement material, such as carbon fiber or wrapping ironplate, having rigidity equivalent to or greater than that of a majordynamic component of the member is bonded directly to the surface of themember by use of resin or the like. The beltlike reinforcement 201, suchas the polyester belt 199, is bonded directly to a member, such as thecolumn 205 is not adapted to suppress formation of the crack 215 on themember surface but is adapted to restrain crack width 217 to aneffective value; for example, to about 2 mm, whereby the functionalimpairment of a member is controlled to thereby maintain usability andsafety of a structure.

A method in which a high-rigidity material, such as the polyester belt199, is bonded directly to the surface of a member is intended toenhance the effect of maintaining the shape of the member with respectto deformation accompanied by finite crack 215. As seen from Eq. 21) toEq. 24), this effect is enhanced in proportion to the circumferentialrigidity of a reinforcement, and the enhancement of the effect islimited by the magnitude of a shear force to be transmitted between thesurface of the member and the reinforcement. Accordingly, through ahigh-rigidity reinforcement being bonded directly to a member, areinforcement effect can be enhanced.

The beltlike reinforcement 201 used in the ninth embodiment is notlimited to the polyester belt 199. Any material having strength andrigidity equivalent to those of the polyester belt 199 can be used.

The reinforcement method is such that, through control of an increase incrack width 217, the expansion of an apparent volume of a member isrestrained. Thus, in principle, the method is identical to that of theprevious application. However, the method employs the mechanism ofrestraining variation in shape and axial strain and is verifiedtheoretically and experimentally, thereby indicating high practicalviability thereof.

Next, a structure for enhancing a reinforcement effect for a memberinvolving an irregular profile and a member-to-member joint of thepresent invention will be described. FIG. 36 is a perspective viewshowing a state in which connecting reinforcements 269 a and 269 b aredisposed on the joint between a column 261 and a beam 263. The beam 263is joined to the column 261 at right-hand and left-hand side surfaces265 b.

The joint between the column 261 and the beam 263 is reinforced by useof two sheetlike connecting reinforcements 269 a and four connectingreinforcements 269 b. The connecting reinforcement 269 a assumes theform of a sheet and is bonded to the column 261 and the beam 263 in sucha manner as to cover the joints between the side surfaces 265 b of thecolumn 261 and the side surface 267 a of the beam 263. A central portionof the connecting reinforcement 269 a is bonded to a side surface 265 aof the column 261 and the right-hand and left-hand side surfaces 265 badjacent to the side surface 265 a. Opposite end portions of theconnecting reinforcement 269 a are bonded to the side surface 267 a ofthe beam 263.

The connecting reinforcement 269 a assumes the form of a sheet and isbonded to the column 261 and the beam 263 in such a manner as to coverthe joint between the side surface 265 b of the column 261 and the sidesurface 267 b of the beam 263. The connecting reinforcements 269 a and269 b are, for example, stretchable, fibrous or rubber sheet materials.

The connecting reinforcements 269 a and 269 b are not necessarilysheetlike reinforcements but may assume the form of a beltlikereinforcement, such as the polyester belt 199. The thickness, width,length, etc. of the connecting reinforcements 269 a and 269 b, eithersheetlike or beltlike, are determined to provide a required amount ofreinforcement.

The connecting reinforcements 269 a and 269 b may be bonded to thecolumn 261 and the beam 263 in a tentative condition but may be bondedin such a manner as to yield strength. Generally, the displacementamplitude of a structure depends greatly on the deformation of amember-to-member joint. Thus, in view of the amount of reinforcementbeing determined by the method shown in step 309 of FIG. 40, which willbe described later, use of the latter bonding is practical.

FIG. 37 is a perspective view showing a state in which a beltlikereinforcements 271 a and 271 b are disposed on the joint between thecolumn 261 and the beam 263. In FIG. 37, a single beltlike reinforcement271 a and two beltlike reinforcements 271 b are disposed in such amanner as to cover the connecting reinforcements 269 a and 269 b whichare disposed as shown in FIG. 36. The beltlike reinforcement 271 a isdisposed on the exterior of a bigger member; i.e., on the exterior ofthe column 261. The beltlike reinforcement 271 a is wound onto thecolumn 261 in such a manner as to be continuously wound between aportion of the column 261 located above the joint between the column 261and the beam 263 and a portion of the column 261 located below the jointwhile obliquely crossing the joint. The beltlike reinforcement 271 b isdisposed on the exterior of a thinner member; i.e., on the exterior ofthe beam 263. The beltlike reinforcement 271 b is independently woundabout the right-hand and left-hand beams 263 joined to the column 261.

The above-described method is repeatedly carried out until a requiredamount of reinforcement is obtained. In FIG. 37, the beltlikereinforcements 271 a and 271 b are disposed in two layers andcross-wound onto the joint between the column 261 and the beam 263.

The beltlike reinforcements 271 a and 271 b are bonded to the column 261and the beam 263 in such a manner as to yield strength. FIG. 38 is asectional view of the joint between the column 261 and the beam 263 onwhich the connecting reinforcements 269 b, etc. are disposed. Thebeltlike reinforcements 271 a and 271 b are disposed on the connectingreinforcement 269 b in a winding condition. The column 261 or the beam263 and the sheetlike connecting reinforcement 269 b are bonded suchthat tension is mutually transmitted via shear resistance of a bondzone. Similarly are bonded the following combinations: the connectingreinforcement 269 b and the beltlike reinforcements 271 a and 271 b; thecolumn 261 or the beam 263 and the connecting reinforcement 269 a; andthe connecting reinforcement 269 a and the beltlike reinforcements 271 aand 271 b.

In case of need, a reinforcement 273 a is wound about the exterior ofthe column 261, and a reinforcement 273 b is wound about the exterior ofthe beam 263. The reinforcements 273 a and 273 b are stretchablesheetlike or beltlike materials.

As described above, according to the reinforced structure, theconnecting reinforcements 269 a and 269 b are disposed on the jointbetween the column 261 and the beam 263 so as to enhance amember-to-member reinforcement effect. Furthermore, the beltlikereinforcement 271 a is cross-wound onto a joint of a bigger member;i.e., about a joint of the column 261, and the beltlike reinforcements271 a and 271 b are wound about the exterior of the column 261 and thatof the beam 263 in layers, to thereby obtain a required amount ofreinforcement.

In FIGS. 36 and 37, the reinforcement is cross-wound onto the joint.However, the reinforcement can be wound about the joint in the form ofthe letter T or the like. Reinforcement is applicable not only to thejoint between a column and a beam but also to the joint between othermembers. The method can be combined with the method using slits orbores. This combined method is particularly effective for reinforcingthe joint between members of greatly different thicknesses or shapes,such as the joint between a slab and a beam or the joint between a walland a beam.

When a sufficient amount of reinforcement can be obtained merely by useof the beltlike reinforcements 271 a and 271 b, the connectingreinforcements 269 a and 269 b can be omitted.

In the above reinforced structure of a structural body, the reinforcingmember is made of a material having high ductility and high bendability,or extensibility, and installed on the surface of or inside a structuremember or substrate through the fixation using an adhesive, so as toconstrain the apparent volume expansion of the structure member tocontrol the change in shape or the damage of the structure member.

A material which is inexpensive and facilitates working and bonding,such as a polyester sheet, is used as a reinforcement material. TheYoung's modulus of such a material is about one-tenth that of concreteor one-hundredth that of iron. Thus, the reinforcement material's effectof bearing part of a load imposed on a member during the elastic stageaccompanied by very small strain as do reinforcing bars of reinforcedconcrete, is very weak; specifically, as weak as the above-mentionedYoung's modulus ratios.

However, when repeated imposition of load induces yielding and crackingof main component materials, such as concrete and iron, of a column;i.e., when plastic deformation begins, the rigidity of the member drops;thus, the method of the previous application exhibits significanteffectiveness. Even after concrete or a like component material of thecolumn assumes a granular form and then a powder form, and ironundergoes significant plastic deformation or ruptures retains thesecomponent materials in a unitary shape, thereby exhibiting thecapability of maintaining an axial force and the capability of resistingan external force, such as bending and shearing.

The reinforced member absorbs very large energy in the above-mentionedsequential repeated-deformation process while maintaining rigidity,thereby preventing the collapse of a structure which would otherwiseresult from reception of an abrupt external force, such as a seismicforce.

FIG. 41 is a diagram showing the relationship between cumulativedeformation and hysteretic absorbed energy with respect to a reinforcedmember on which a repeated load is imposed. The horizontal axisrepresents cumulative deformation, and the vertical axis representshysteretic absorbed energy. As a result of a repeated external forcebeing imposed on a member during the member being deformed withinvolvement of finite cracking, component materials of the member arepartially ruptured. A shear force transmitted between the member and areinforcement decreases accordingly. As a result, a reinforcement effectweakens, and the effect of retaining the shape of the member alsoweakens. The rupture of component materials of the member induced as aresult of reception of a repeated load can be measured in terms of workdone by the external force; i.e., in terms of hysteretic absorbedenergy.

A certain limit (called a shape retainment limit energy 275) is presentaccording to the type and amount of material. When this limit isexceeded, a material behaves in a granular fashion, and thus the shapeof a member begins to vary significantly. A member reinforced accordingto a method of the present invention or the previous application isdeformed such that the cross section assumes a circular shape, and theentire shape approaches to the shape of linked balls. Accordingly, theshape of a structure also varies significantly.

The method of the present application is characterized by being able tocope with a wide energy region and a wide deformation region, and anenhancement of an effect to be yielded as shown in FIG. 41. When themethod of the present invention are applied to a seismic isolator, theseismic isolator can absorb energy in such an amount that a materialhaving a volume equivalent to that of the seismic isolator is pulverizedsubstantially completely, while variation in shape is minimized, andrigidity is retained. This is a very efficient behavior for a seismicisolator. When a special filler is mixed into a component material of aseismic isolator, the filler functions to internally reinforce thematerial through utilization of energy, such as heat, to be generated bywork which is done by an external force in the above-mentioned process,thereby further enhancing a seismic isolation effect.

Next, the fibrous sheetlike reinforcements and beltlike reinforcementsas mentioned above are impregnated with resin will be described. FIG. 42is a graph showing the relationship between tensile stress and strainwith respect to a reinforcement material impregnated with resin and areinforcement material unimpregnated with resin. The vertical axisrepresents tension, and the horizontal axis represents extensionalstrain (%).

An impregnated-with-resin curve 277 shows the stress-strain relationobtained from a tensile test which was conducted on a polyestersheetlike textile impregnated with epoxy resin after the resin wascured. An unimpregnated-with-resin curve 279 shows the stress-strainrelation obtained from a tensile test which was conducted on the samesheetlike textile unimpregnated with epoxy resin.

Comparison in FIG. 42 between the impregnated-with-resin curve 277 andthe unimpregnated-with-resin curve 279 shows the following: as a resultof impregnation with resin, rigidity; i.e., the gradient of the partingline of the graph, is significantly large at a strain of 0% to about 3%;and deformation can be maintained without rupture until large strain isreached. Similar test results are also obtained from a polyesterbeltlike material, such as the polyester belt 199 shown in FIG. 21.

The test results shown in FIG. 42 show the following: as a result of asheet or beltlike material woven from polyester fiber being impregnatedwith resin, resin yields the effect of restraining deformation of fiberfor the range of small strain; thus, the material represented by theimpregnated-with-resin curve 277 exhibits increased rigidity as comparedwith the material represented by the unimpregnated-with-resin curve 279.When deformation increases, the material represented by theimpregnated-with-resin curve 277 loses the above-mentioned effectwithout significant breakage of fiber. As a result, deformation can bemaintained until a large strain of not less than 15% is reached.

Thus, through a reinforcement material impregnated with resin; i.e., amaterial of a single kind, enhances the effect of restrainingdeformation for the range of small strain as well as yields the effectof bearing a load for the range of large strain.

The aforementioned reinforcing member can be designed as follows.

As described above, the dynamic property (the relationship betweenexternal force and deformation) of the reinforced structure is definedby the following parameters. Thus, the reinforced structure can bedesigned by calculating the performance of a structural body subject toreinforcement, according to these parameters and data of the structuralbody.

1) Thickness of reinforcing member t

2) Young's modulus of reinforcing member E_(f)

3) Fracture strain of reinforcing member ε_(fb)

4) Reinforcing-member stress at yield of fixation structure τ_(fmax)

5) Reinforcing-member installation mode (Whether reinforcing-member isclosingly looped (FIG. 1) or not (FIG. 3))

6) Reinforcing-member installation range (When not closingly looped)expressed by b

7) Peeling-limit elongation δ1

For determination of reinforcing-member stress at yield of fixationstructure, the following 8) or 9) can be used.

8) Constraint length b and Average fixation strength τ_(f)

9) Peeling energy of boundary surface of fixation structure G_(f)

Further, the gap width and reinforcing-member tensile force in aSRF-reinforced structure has a relationship as shown in FIG. 44.Specifically, if the gap width is increased from zero, a reinforcingmember will be elongated in a fixation zone, and thereby areinforcing-member stress will be generate. When the elongation of thereinforcing member on the gap reaches δ1, the release of the fixationstructure is initiated to generate a free length a (FIG. 44). If thefixation is based on bonding, and the reinforcing member is bonded evenat a position sufficiently away from the gap, the fixation force will bekept at an approximately constant value as long as a constraint length(the distance between the gap and a position where the fixation force isnot zero) can be increased in conjunction with the increase of the gapwidth (FIG. 4). This is the range from Point A to Point B in FIG. 44.Subsequently, a fixation length (s=b−a) is reduced, and thus thereinforcing-member stress is reduced. This is the range from Point B toPoint C. According to the theory shown in the expressions [1] to [4],the bonding is released all at once when the reinforcing-member stressbecomes half of its maximum value. If the reinforcing member isclosingly looped, or a geometrical constraint exists at the corner ofthe structure member or the like, the fixation force will be maintainedto increase a reinforcing-member tensile force in proportion to the gapwidth until the reinforcing member reaches a fracture stress (stresscorresponding to the fracture strain ε_(fb)) (range from Point C toPoint D).

For example, in case of a bar-shaped structure member, the relationshipbetween reinforcing-member tensile force and restoring force can bedetermined from the theory as shown in the expressions [9] and [10], oran experimental test. Further, the reinforcing-member elongation δ₁providing the maximum value of the reinforcing-member tensile force is avalue derived from integrating strains in the fixation zone of thereinforcing member at the time of the limit where the bonding isreleased (when the reinforcing-member tensile force reaches τ_(fmax)),and becomes smaller as the Young's modulus of the reinforcing member isincreased. This factor is ignored in the theory shown in the expressions[1] to [4].

The maximum reinforcing-member tensile force may be derived fromdividing the product of the restraint length and the average bondingstrength by the reinforcing-member thickness from the expression [4].However, if the reinforcing member is wounded around a structure member,and the structure member is installed over a wide range, the constraintlength cannot be figured out in some cases. This problem can be solvedby determining the maximum reinforcing-member tensile force using theboundary-surface peeling energy in the following expression [101]:$\begin{matrix}{\sigma_{f\quad\max} = \sqrt{\frac{2E_{f}G_{f}}{t}}} & \lbrack 101\rbrack\end{matrix}$

The boundary-surface peeling energy is defined as energy required forpeeling the bonding boundary-surface of unit area between a thin elasticbody and a substrate as shown in FIG. 44, and can be calculated from thefollowing expression [102] using the maximum tensile force σ_(fmax)caused in the elastic body and the thickness t and Young's modulus ofthe elastic body, which are obtained as the reinforcing bar. Further,while a maximum reinforcing-member tensile force σ_(fmax) is calculatedusing the expression [101], it is given that the reinforcing-memberstress does not go beyond a value corresponding a reinforcing-memberstrain of 1%.

The above apparent yield stress (σ_(fmax) in the expressions [101] and[102]) is a maximum stress capable of being borne before the fixation ofthe reinforcing member is released (FIG. 45), and calculated from theYoung's modulus of the reinforcing member, the boundary-surface peelingenergy and the thickness of the reinforcing member using the expression[101]. In the expression [101], the apparent yield stress is reduced inreverse proportion to the square root of the thickness. Thus, thereinforcing-member thickness can be determined by a simple repeatedcalculation.

As above, while the present invention has been described in conjunctionwith preferred embodiments of a reinforced structure, reinforcingmethod, quake-absorbing structure, and reinforcing member for astructural body according to the present invention, the presentinvention is not limited to such embodiments. It is obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit and scope of the presentinvention. Therefore, it is intended that such changes and modificationsare obviously encompassed within the scope of the present invention.

Industrial Applicability

As mentioned above, the present invention can provide a reinforcingmaterial or member excellent in ductility and load-withstandingcapacity, quickly at a low cost. result of a peeling test.$\begin{matrix}{G_{f} = {\frac{t}{2E_{f}}\sigma_{f\quad\max}^{2}}} & \lbrack 102\rbrack\end{matrix}$

The expression [101] is obtained by resolving the formula [102] aboutσ_(fmax).

In a design for SRF-reinforcing a reinforced concrete structure member,a conventional design formula for reinforced concrete structure memberscan be applied to the calculation of the reinforcement effect of a SRFreinforcing member by substituting the SRF reinforcing member with areinforcing bar and calculating the reinforcement effect using theboundary-surface peeling energy etc. by use of the phenomenon that a SRFreinforcing member apparently yields at σ_(fmax) as shown in FIG. 55(expression [103]). However, there is possibility that the gap width inthe design limit state does not reach the peeling-limit elongation δ1illustrated in FIGS. 44 and 55 due to a small Young's modulus of the SRFreinforcing member as compared to that of reinforcing bar. Thus, it isrequired to take notice of checking whether δ₁ is caused within thedesign limit, through an experimental test or the like, or putting alimit on the reinforcing-member stress.

For example, in a design for a SRF reinforcing member installed based onbonding in such a manner that it is wounded around a bar-shapedreinforced concrete structure member shown in FIG. 7, an equivalentshear reinforcing bar amount P_(wf) after reinforcement is calculated asfollows: $\begin{matrix}{P_{wf} = {P_{w} + {\frac{2t}{b_{m}}\frac{\sigma_{f\quad\max}}{\sigma_{sy}}}}} & \lbrack 103\rbrack\end{matrix}$wherein t is the thickness of the reinforcing member, bm being the widthof the section of the structure member, pw being the ratio of the shearreinforcing bar to the structure member subject to reinforcement, andσ_(sy) being a yield stress of the The effects of the reinforcing memberaccording to the present invention is effective to repair, maintenanceand reinforcement of existing structure bodies, and usable in newstructural bodies. In either case, the cost, construction period etc.required for satisfying a desired performance can be reduced as comparedto those in conventional techniques. The reinforcing material or memberaccording to the present invention is useable as a safeguard againstsudden external forces such as explosion, which have been untreatable byconventional techniques. In addition, the reinforcing member installedon the outer surface of a structure member as a primary element thereofmakes it possible to provide a reinforced structure readily at a lowcost and achieve enhanced reinforcement performance. Furthermore, thepresent invention facilitates reuse of decrepit or affected structuralbodies to promote effective use of existing structural bodies andindustrial resources and to allow industrial wastes to be reduced.

Moreover, a reinforcement configuration, a seismic isolator, and areinforcement method for a structure according to the present inventioncan suitably be applied to, for example, the following cases: a memberto be reinforced involves undulation or an irregular profile; a memberis joined to or located in proximity to another member or anonstructural member; a reinforcement is possibly deteriorated due tointeraction between a member and the reinforcement or between thereinforcement and an external environment; a reinforcement effect mustencompass a small deformation through a large deformation; andseismically isolating reinforcement is required.

1-64. (canceled)
 65. A reinforcing member to be installed on a member ormembers of a structure to reinforce said member or members, having ahigh bendability to fit an edge or edges of said member or members, andto follow a deformation of said member or members without breaking saidmember or members so as to maintain a reinforcement effect.
 66. Thereinforcing member as defined in claim 65, which has a bendingdeformation angle of 90-degree or more.
 67. The reinforcing member asdefined in claim 65, which has a shear deformation angle of 2-degree ormore.
 68. A reinforcing member to be installed on a member or members ofa structure to reinforce said member or members, having a highbendability and an elasticity, with a Young's modulus not greater thanthat of said member or members to follow a deformation of said member ormembers without breaking said member or members so as to maintain areinforcement effect.
 69. The reinforcing member as defined in claim 68,wherein the Young's modulus is to be a product specification value. 70.A reinforcing member to be installed on a member or members of astructure to reinforce said member or members, wherein in saidreinforcing member a design size thereof is determined by the product ofa Young's modulus and thickness.
 71. The reinforcing member as definedin claim 65, which is formed by a weaving process.
 72. A reinforcingmember to be installed on a member or members of a structure toreinforce said member or members having an elasticity and a highductility, with a tensile fracture strain thereof greater than that ofsaid member or members to follow a deformation of said member or memberswithout breaking said member or members so as to maintain areinforcement effect.
 73. The reinforcing member as defined in claim 72,wherein the tensile fracture strain is 10% or more.
 74. A reinforcingmember to be installed on a member or members of a structure toreinforce said member or members, wherein in said reinforcing member atensile fracture strain is a product specification value.
 75. Areinforcing member to be installed on a member or members of a structureto reinforce said member or members, said reinforcing member having anelasticity and a high ductility, with a Young's modulus in the range of500 to 50,000 Mpa to follow a deformation of said member or memberswithout breaking said member or members so as to maintain areinforcement effect.
 76. The reinforcing member as defined in claim 65,which comprises a woven body being heat-set to allow a Young's modulusin a design limit state to be greater.
 77. The reinforcing member asdefined in claim 65, which is made of a rubber-based or resin-basedelastic material.
 78. A fixation material to be used for a reinforcingmember to be installed on a member or members of a structure toreinforce said member or members, wherein in said fixation material astrength thereof is lower than a fracture strength of said member ormembers.
 79. An adhesive to be used for a reinforcing member to beinstalled on a member or members of a structure to reinforce said memberor members, wherein in said adhesive a strength thereof is lower than afracture strength of said member or members.
 80. An adhesive to be usedfor a reinforcing member to be installed on a member or members of astructure to reinforce said member or members, wherein said adhesiveboundary-surface peeling energy is to be a product specification value,thereby a breaking of said adhesive layer does not cause breaking saidmember or members.
 81. An adhesive to be used for a reinforcing memberto be installed on a member or members of a structure to reinforce saidmember or members, said adhesive not applying a solvent, to therebyremove a harmful effect to a human body.
 82. An adhesive to be used fora reinforcing member to be installed on a member or members of astructure to reinforce said member or members, said adhesive being aone-component, to thereby simplify a fixation process.
 83. A reinforcingstructure comprising a reinforcing member to be installed on a member ormembers of a structure to reinforce said member or members, saidreinforcing structure having a high bendability to fit an edge or edgesof said member or members, and to follow a deformation of said member ormembers without breaking said member or members so as to maintain areinforcement effect.
 84. A reinforcing structure comprising areinforcing member to be installed on a member or members of a structureto reinforce said member or members, wherein in said reinforcingstructure said reinforcing member has a high bendability and anelasticity, with a Young's modulus not greater than that of said memberor members to follow a deformation of said member or members so as tomaintain a reinforcement effect.
 85. A reinforcing structure comprisinga reinforcing member to be installed on a member or members of astructure to reinforce said member or members, wherein in saidreinforcing structure said reinforcing member has a high bendability andan elasticity, with a Young's modulus in the range of 500 to 50,000 Mpato follows a deformation of said member or members so as to maintain areinforcement effect.
 86. A reinforcing structure comprising areinforcing member to be installed on a member or members of a structureto reinforce said member or members, wherein in said reinforcingstructure said reinforcing member allows a flexural rigidity and shearrigidity to be low, to thereby prevent said reinforcing member breakingsaid member or members till after said member or members deformed. 87.The reinforcing structure as defined in claim 84, wherein a reinforcingmember, which has a Young's modulus to be a product specification value,is installed.
 88. A reinforcing structure comprising a reinforcingmember to be installed on a member or members of a structure toreinforce said member or members, wherein in said reinforcing structurea design size thereof is determined by the product of a Young's modulusand thickness of said reinforcing member.
 89. A reinforcing structurecomprising a reinforcing member to be installed on a member or membersof a structure to reinforce said member or members, wherein in saidreinforcing structure said reinforcing member has an elasticity and ahigh ductility, with a tensile fracture strain thereof not greater thanthat of said member or members, to thereby maintain practically a loadof said member or members till after said member or members broken. 90.A reinforcing structure comprising a reinforcing member to be installedon a member or members of a structure to reinforce said member ormembers, wherein in said reinforcing structure said reinforcing memberhas a high ductility and elasticity, with a Young's modulus in the rangeof 500 to 50,000 Mpa, to thereby prevent said reinforcing memberbreaking said member or members till after said member or membersdeformed.
 91. The reinforcing structure as defined in claim 89, whereina tensile fracture strain of said reinforcing member is 10% or more. 92.A reinforcing structure comprising a reinforcing member to be installedon a member or members of a structure to reinforce said member ormembers, wherein in said reinforcing structure said reinforcing memberhas a tensile fracture strain to be a product specification value.
 93. Areinforcing structure comprising a reinforcing member to be installed ona member or members of a structure to reinforce said member or members,wherein in said reinforcing structure said reinforcing member, which hasa high bendability, is installed without chamfering of said member ormembers or grouting between spaces of said member or members, andfollows a deformation of said member or members so as to maintain areinforcement effect.
 94. A reinforcing structure comprising areinforcing member to be installed on a member or members of a structureto reinforce said member or members, wherein in said reinforcingstructure said reinforcing member is installed on said member or membersthrough a filler material in a space between the reinforcing member andsaid member or members, and a shear strength of said filler material islower than said member or members and said reinforcing member, tothereby maintain a reinforcement effect by confining an apparent volumeexpansion till after said member or members deformed.
 95. A reinforcingstructure comprising a reinforcing member to be installed on a member ormembers of a structure to reinforce said member or members, wherein insaid reinforcing structure said reinforcing member, which comprises aplurality of materials having a variant Young's modulus and fracturestrain, is installed, to thereby maintain a reinforcement effect from anearly stage of said member or members deformed till after said member ormembers broken.
 96. A reinforcing structure comprising a reinforcingmember to be fixed on a member or members of a structure to reinforcesaid member or members, wherein in said reinforcing structure a fixationstrength is lower than a fracture strength of said member or members,thereby a breaking of a fixation part does not occur.
 97. Thereinforcing structure as defined in claim 96, wherein said fixationessentially consists of an adhesive.
 98. A reinforcing structurecomprising a reinforcing member to be installed on a member or membersof a structure by an adhesive to reinforce said member or members,wherein in said reinforcing structure said adhesive is a non-solventadhesive, thereby no harmful effect is given to a human health.
 99. Areinforcing structure comprising a reinforcing member to be installed ona member or members of a structure by an adhesive to reinforce saidmember or members, wherein in said reinforcing structure said adhesiveis a one-component, thereby a reinforcing structure forming process issimplified.
 100. A reinforcing structure comprising a reinforcing memberto be installed on a member or members of a structure by an adhesive toreinforce said member or members, wherein in said reinforcing structuresaid adhesive has a boundary-surface peeling energy to be a productspecification value, thereby a breaking of said adhesive layer does notcause breaking said member or members.
 101. A reinforcing structurecomprising a reinforcing member to be fixed on a member or members of astructure to reinforce said member or members, wherein in saidreinforcing structure a size of said reinforcing member is determined soas to obtain a required reinforcement effect by fixation strength orboundary-surface peeling energy.
 102. A reinforcing method comprising areinforcing member to be installed on a member or members of a structureto reinforce said member or members, wherein in said reinforcing methodsaid reinforcing member has a high bendability to fit an edge or edgesof said member or members, and to follow a deformation of said member ormembers without breaking said member or members so as to maintain areinforcement effect.
 103. A reinforcing method comprising a reinforcingmember to be installed on a member or members of a structure toreinforce said member or members, wherein in said reinforcing methodsaid reinforcing member, which has a high bendability and an elasticity,with a Young's modulus equal to or less than that of said member ormembers, is installed, and follows a deformation of said member ormembers without breaking said member or members so as to maintain areinforcement effect.
 104. A reinforcing method comprising a reinforcingmember to be installed on a member or members of a structure toreinforce said member or members, wherein in said reinforcing method adesign size thereof is determined by the product of a Young's modulusand thickness of said reinforcing member.
 105. The reinforcing method asdefined in claim 103, wherein said reinforcing member, which has aYoung's modulus to be a product specification value, is installed. 106.A reinforcing method comprising a reinforcing member to be installed ona member or members of a structure to reinforce said member or members,wherein in said reinforcing method said reinforcing member, which has atensile fracture strain to be a product specification value, isinstalled.
 107. A reinforcing method comprising a reinforcing member tobe installed on a member or members of a structure to reinforce saidmember or members, wherein in said reinforcing method said reinforcingmember, which has an elasticity and a high ductility, with tensilefracture strain thereof equal to or more than that of said member ormembers, is installed, to thereby maintain practically a load of saidmember or members till after said member or members broken.
 108. Areinforcing method comprising a reinforcing member to be installed on amember or members of a structure to reinforce said member or members,wherein in said reinforcing method said reinforcing member, which has ahigh ductility and an elasticity, with a Young's modulus in the range of500 to 50,000 Mpa, is installed, and follows a deformation of saidmember or members so as to maintain a reinforcement effect.
 109. Thereinforcing method as defined in claim 104, wherein a tensile fracturestrain of said reinforcing member is 10% or more.
 110. A reinforcingmethod comprising a reinforcing member to be installed on a member ormembers of a structure to reinforce said member or members, wherein insaid reinforcing method said reinforcing member, which has a highbendability, is installed without chamfering of said member or membersor grouting between spaces of said member or members, to therebymaintain a reinforcement effect till after said member or membersdeformed.
 111. A reinforcing method comprising a reinforcing member tobe installed on a member or members of a structure to reinforce saidmember or members, wherein in said reinforcing method said reinforcingmember is installed between spaces of said member or members through afiller material whose shear strength is lower than said member ormembers and said reinforcing member, to thereby maintain a reinforcementeffect by confining an apparent volume expansion till after said memberor members deformed.
 112. A reinforcing method comprising a reinforcingmember to be installed on a member or members of a structure toreinforce said member or members, wherein in said reinforcing methodsaid reinforcing member, which comprises a plurality of materials havinga variant Young's modulus and fracture strain, is installed, to therebymaintain a reinforcement effect from an early stage of said member ormembers deformed till after said member or members broken.
 113. Areinforcing method comprising a reinforcing member to be installed on amember or members of a structure to reinforce said member or members,wherein in said reinforcing method a fixation strength allows to be lessthan a fracture strength of said structural member, thereby breaking afixation part does not occur.
 114. The reinforcing method as defined inclaim 114, wherein said fixation essentially consists of an adhesive.115. A reinforcing method comprising a reinforcing member to beinstalled on a member or members of a structure to reinforce said memberor members, wherein in said reinforcing method said adhesive is anon-solvent adhesive, thereby no harmful effect is given to a humanhealth.
 116. A reinforcing method comprising a reinforcing member to beinstalled on a member or members of a structure to reinforce said memberor members, wherein in said reinforcing method said adhesive is aone-component, thereby a reinforcing structure forming process issimplified.
 117. A reinforcing method comprising a reinforcing member tobe installed on a member or members of a structure to reinforce saidmember or members, wherein in said reinforcing method an adhesive, whichhas a boundary-surface peeling energy to be a product specificationvalue, is applied.
 118. The reinforcing structure as defined in claim82, wherein said member or members is at least one selected from thegroup consisting of: concrete; steel frame; brick; block; gypsum boardor plaster board; wood; rock; earth or soil; sand; resin; and metal.119. The reinforcing method as defined in claim 83, wherein said memberor members is at least one selected from the group consisting of:concrete; steel frame; brick; block; gypsum board or plaster board;wood; rock; earth or soil; sand; resin; and metal.